presentation on topic hormones

The Endocrine System

Controls many body functions
exerts control by releasing special chemical substances into the blood called hormones
Hormones affect other endocrine glands or body systems
Derives its name from the fact that various glands release hormones directly into the blood, which in turn transports the hormones to target tissues via ducts.
Consists of several glands located in various parts of the body.
Pituitary gland : a small gland located on a stalk hanging from the base of the brain - AKA
“ The Master Gland”
Primary function is to control other glands.
Produces many hormones.
Secretion is controlled by the hypothalamus in the base of the brain.
The Pituitary Gland is divided into 2 areas, which differ
structurally and functionally
each area has separate types of hormone production.
The two segments are:
Posterior Pituitary:
produces oxytocin and antidiuretic hormone ( ADH )
Anterior Pituitary:
produces thyroid-stimulating hormone ( TSH )
growth hormone ( GH )
adrenocorticotropin ( ACTH )
follicle-stimulating hormone ( FSH )
And even more…
luteinizing hormone ( LH )
Let’s go over these one at a time...
Posterior Pituitary
Oxytocin (the natural form of pitocin)
stimulates gravid uterus
causes “let down” of milk from the breast.
ADH (vasopressin) causes the kidney to retain water.
Anterior Pituitary
Primarily regulates other endocrine glands
rarely a factor in endocrinological emergencies
TSH stimulates the thyroid gland to release its hormones, thus ↑ metabolic rate
Anterior Pituitary…
Growth hormone ( GH )
↓ glucose usage
↑ consumption of fats as an energy source
ACTH stimulates the adrenal cortex to release its hormones
FSH & LH stimulates maturation & release of eggs from ovary.
The Thyroid Gland
lies in the anterior neck just below the larynyx.
Two lobes, located on either side of the trachea, connected by a narrow band of tissue called the isthmus .
Sacs inside the gland contain colloid
Within the colloid are the thyroid hormones:
thyroxine ( T4 )
triiodothyronine ( T3 )
When stimulated (by TSH or by cold), these are released into the circulatory system and ↑ the metabolic rate.
“C” cells within the thyroid produce the hormone calcitonin .
Calcitonin , when released, lowers the amount of calcium in the blood.
Inadequate levels of thyroid hormones = hypothyroidism, or Myxedema.
Myxedema symptoms:
Facial bloating
cold intolerance
altered mental status
oily skin and hair
TX: replacement of thyroid hormone.
Increased thyroid hormone release causes hyperthyroidism, commonly called Graves’ disease.
Signs and symptoms:
insomnia, fatigue
tachycardia
hypertension
heat intolerance
weight loss
Long term hyperthyroidism:
Exopthalmos
bulging of the eyeballs (picture Barbara Bush)
In severe cases - a medical emergency called thyrotoxicosis can result.
Parathyroid Glands
small, pea-shaped glands, located in the neck near the thyroid
usually 4 - number can vary
regulate the level of calcium in the body
produce parathyroid hormone - ↑ level of calcium in blood
Hypocalcemia can result if parathyroids are removed or destroyed.
a key gland located in the folds of the duodenum
has both endocrine and exocrine functions
secretes several key digestive enzymes
Islets of Langerhans
specialized tissues in which the endocrine functions of the pancreas occurs
include 3 types of cells:
each secretes an important hormone.
Alpha (α) cells release glucagon , essential for controlling blood glucose levels.
When blood glucose levels fall, α cells ↑ the amount of glucagon in the blood .
The surge of glucagon stimulates the liver to release glucose stores (from glycogen and additional storage sites).
Also, glucagon stimulates the liver to manufacture glucose -
gluconeogenesis.
Beta Cells (β) release insulin (antagonistic to glucagon).
Insulin ↑ the rate at which various body cells take up glucose. Thus, insulin lowers the blood glucose level.
Insulin is rapidly broken down by the liver and must be secreted constantly.
Delta Cells ( ∂ ) produce somatostatin, which inhibits both glucagon and insulin.
Adrenal Glands
2 small glands that sit atop both kidneys.
secretes the hormones norepinephrine and epinephrine (closely related to the sympathetic component of the autonomic nervous system).
accounts for 95% of adrenal cortex hormone production
↑ the level of glucose in the blood
Released in response to stress, injury, or serious infection
Gonads and Ovaries :
the endocrine glands associated with human reproduction.
Female ovaries produce eggs
Male gonads produce sperm
both have endocrine functions.
located in the abdominal cavity adjacent to the uterus.
Under the control of LH and FSH from the anterior pituitary they manufacture
protesterone
Estrogen and Progesterone have several functions, including sexual development and preparation of the uterus for implantation of the egg.
located in the scrotum
produce sperm for reproduction
manufacture testosterone -
promotes male growth and masculinization
Controlled by anterior pituitary hormones FSH and LH.
Endocrine Emergencies:
Diabetes Mellitus
one of the most common diseases in North America.
↓ insulin secretion by the Beta (β) cells of the islets of Langerhans in the pancreas.
Complications of Diabetes:
contributes to heart disease
kidney disease
Pathophysiology of Diabetes:
Glucose Metabolism
Glucose (dextrose) is a simple sugar required by the body to produce energy.
Sugars, or carbohydrates, are 1 of 3 major food sources used by the body.
The other 2 major food sources are
Most sugars in the human diet are complex and must be broken down into simple sugars: glucose, galactose and fructose - before use.
Breakdown of sugars is carried out by enzymes in the gastro intestinal system.
As simple sugars, these are absorbed from the GE system into the body.
More than 95% enter the body as glucose.
To be converted into energy, glucose must first be transmitted through the cell membrane. BUT - the glucose molecule is large and doesn’t readily diffuse through the cell membrane.
Glucose must pass into the cell by binding to a special carrier protein on the cell’s surface.
Facilitated diffusion - doesn’t use energy . The carrier protein binds with the glucose and carries it into the cell.
The rate at which glucose can enter the cell is dependent upon insulin levels.
Insulin serves as the messenger - travels via blood to target tissues.
Combines with specific insulin receptors on the surface of the cell membrane.

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Hormones: Overview and Types

Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. The work of hormones allows the body to maintain homeostasis Homeostasis The processes whereby the internal environment of an organism tends to remain balanced and stable. Cell Injury and Death and regulate growth and development. Hormones are typically either made from amino acids Amino acids Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins. Basics of Amino Acids or derived from cholesterol Cholesterol The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils. Cholesterol Metabolism (the latter group being known as steroid hormones). Hormones exert their effects by binding to receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors either on the cell surface (most amino acid Amino acid Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). Basics of Amino Acids –based hormones) or within the cytosol Cytosol A cell's cytoskeleton is a network of intracellular protein fibers that provides structural support, anchors organelles, and aids intra- and extracellular movement. The Cell: Cytosol and Cytoskeleton (steroid hormones). Ultimately, binding to receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors triggers changes in gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics expression or enzymatic activity within the cell.

Last updated: Apr 18, 2023

Hormones and Endocrine Glands

Types of hormones, hormone signaling, clinical relevance.

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Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body.

General functions of hormones

Major functions of hormones include:

Physical stress (e.g., injury, exercise)
Biochemical stress (e.g., ↓ blood sugar, hyperkalemia Hyperkalemia Hyperkalemia is defined as a serum potassium (K+) concentration >5.2 mEq/L. Homeostatic mechanisms maintain the serum K+ concentration between 3.5 and 5.2 mEq/L, despite marked variation in dietary intake. Hyperkalemia can be due to a variety of causes, which include transcellular shifts, tissue breakdown, inadequate renal excretion, and drugs. Hyperkalemia , hypercalcemia Hypercalcemia Hypercalcemia (serum calcium > 10.5 mg/dL) can result from various conditions, the majority of which are due to hyperparathyroidism and malignancy. Other causes include disorders leading to vitamin D elevation, granulomatous diseases, and the use of certain pharmacological agents. Symptoms vary depending on calcium levels and the onset of hypercalcemia. Hypercalcemia )
Mental stress (e.g., fear/danger)
Coordinating cellular and tissue responses between multiple organ systems
Growth and development
Biologic rhythms (e.g., circadian sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep cycles, menstrual cycle Menstrual cycle The menstrual cycle is the cyclic pattern of hormonal and tissular activity that prepares a suitable uterine environment for the fertilization and implantation of an ovum. The menstrual cycle involves both an endometrial and ovarian cycle that are dependent on one another for proper functioning. There are 2 phases of the ovarian cycle and 3 phases of the endometrial cycle. Menstrual Cycle )
Digestion Digestion Digestion refers to the process of the mechanical and chemical breakdown of food into smaller particles, which can then be absorbed and utilized by the body. Digestion and Absorption

Endocrine glands Endocrine glands Ductless glands that secrete hormones directly into the blood circulation. These hormones influence the metabolism and other functions of cells in the body. Glandular Epithelium: Histology and organs

The major endocrine glands Endocrine glands Ductless glands that secrete hormones directly into the blood circulation. These hormones influence the metabolism and other functions of cells in the body. Glandular Epithelium: Histology in the body include:

Hypothalamus Hypothalamus The hypothalamus is a collection of various nuclei within the diencephalon in the center of the brain. The hypothalamus plays a vital role in endocrine regulation as the primary regulator of the pituitary gland, and it is the major point of integration between the central nervous and endocrine systems. Hypothalamus
Pineal gland
Thyroid Thyroid The thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck. Thyroid Gland: Anatomy gland
Parathyroid Parathyroid The parathyroid glands are 2 pairs of small endocrine glands found in close proximity to the thyroid gland. The superior parathyroid glands are lodged within the parenchyma of the upper poles of the right and left thyroid lobes; the inferior parathyroid glands are close to the inferior tips or poles of the lobes. Parathyroid Glands: Anatomy gland
Pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy
Stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy
Adrenal cortex Adrenal Cortex The outer layer of the adrenal gland. It is derived from mesoderm and comprised of three zones (outer zona glomerulosa, middle zona fasciculata, and inner zona reticularis) with each producing various steroids preferentially, such as aldosterone; hydrocortisone; dehydroepiandrosterone; and androstenedione. Adrenal cortex function is regulated by pituitary adrenocorticotropin. Adrenal Glands: Anatomy
Adrenal medulla Adrenal Medulla The inner portion of the adrenal gland. Derived from ectoderm, adrenal medulla consists mainly of chromaffin cells that produces and stores a number of neurotransmitters, mainly adrenaline (epinephrine) and norepinephrine. The activity of the adrenal medulla is regulated by the sympathetic nervous system. Adrenal Glands: Anatomy
Testes Testes Gonadal Hormones
Ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries: Anatomy
Placenta Placenta A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (chorionic villi) derived from trophoblasts and a maternal portion (decidua) derived from the uterine endometrium. The placenta produces an array of steroid, protein and peptide hormones (placental hormones). Placenta, Umbilical Cord, and Amniotic Cavity

Major organs of the endocrine system

Amino acid Amino acid Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). Basics of Amino Acids –based hormones

Most hormones are amino acid Amino acid Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). Basics of Amino Acids –based.

Most commonly derived from tyrosine Tyrosine A non-essential amino acid. In animals it is synthesized from phenylalanine. It is also the precursor of epinephrine; thyroid hormones; and melanin. Synthesis of Nonessential Amino Acids
Example: epinephrine Epinephrine The active sympathomimetic hormone from the adrenal medulla. It stimulates both the alpha- and beta- adrenergic systems, causes systemic vasoconstriction and gastrointestinal relaxation, stimulates the heart, and dilates bronchi and cerebral vessels. Sympathomimetic Drugs
Short amino acid Amino acid Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). Basics of Amino Acids chains
Example: insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin
Long amino acid Amino acid Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). Basics of Amino Acids chains
Example: epidermal growth factor
May have a carbohydrate component → glycoproteins Glycoproteins Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins. Basics of Carbohydrates
Travel freely to site of action
Relatively shorter half-life Half-Life The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity. Pharmacokinetics and Pharmacodynamics as compared with steroid hormones
Exception: thyroid Thyroid The thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck. Thyroid Gland: Anatomy hormones → amino acid Amino acid Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). Basics of Amino Acids –derived hormones that have intracellular receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors

Steroid hormones

Synthesized from cholesterol Cholesterol The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils. Cholesterol Metabolism → lipophilic
Proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis function as a reservoir Reservoir Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (disease vectors) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks. Humans may serve both as disease reservoirs and carriers. Escherichia coli .
Relatively longer half-life Half-Life The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity. Pharmacokinetics and Pharmacodynamics , as compared with amino acid Amino acid Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). Basics of Amino Acids hormones
Are able to move through the cell membrane Cell Membrane A cell membrane (also known as the plasma membrane or plasmalemma) is a biological membrane that separates the cell contents from the outside environment. A cell membrane is composed of a phospholipid bilayer and proteins that function to protect cellular DNA and mediate the exchange of ions and molecules. The Cell: Cell Membrane ’s lipid bilayer → steroid hormones bind BIND Hyperbilirubinemia of the Newborn to receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors within cells
Adrenal hormones Adrenal hormones There are 2 primary portions of the adrenal glands, the adrenal medulla and the adrenal cortex. The adrenal medulla is the inner portion of the gland, secreting epinephrine and, to a lesser degree, norepinephrine. The adrenal cortex is the outer portion of the gland and secretes mineralocorticoids, glucocorticoids, and androgens. Adrenal Hormones
Gonadal hormones Gonadal hormones The gonadal hormones are produced by the human gonads: the testes and the ovaries. The primary hormones produced by these organs include androgens, estrogens, and progestins. Testosterone is the primary androgen, and estradiol and progesterone are the primary female hormones. Gonadal Hormones

Most hormones bind BIND Hyperbilirubinemia of the Newborn to receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors , which then convey their message through secondary messengers and/or signal cascades. Steroid hormones, when bound to their receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors , are able to directly bind BIND Hyperbilirubinemia of the Newborn DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure and affect gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics expression.

Modes of communication Communication The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups. Decision-making Capacity and Legal Competence

There are several ways hormones send messages throughout the body:

Endocrine hormones: released from specialized cells and travel through the blood to a distant site of action (true hormones)
Paracrine hormones: released into the interstitial fluid Interstitial fluid Body Fluid Compartments to act on neighboring cells
Autocrine hormones: Cells release hormones to regulate themselves.
Neuroendocrine hormones: Neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology release a neurohormone that is carried through the blood to its distant site of action.

Signaling via plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products memrane hormone receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors

Plasma membrane Plasma membrane A cell membrane (also known as the plasma membrane or plasmalemma) is a biological membrane that separates the cell contents from the outside environment. A cell membrane is composed of a phospholipid bilayer and proteins that function to protect cellular DNA and mediate the exchange of ions and molecules. The Cell: Cell Membrane receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors are typically required for amino acid Amino acid Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). Basics of Amino Acids –based hormones and use 2nd-messenger systems and signal cascades:

A hormone binding to its receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors triggers release of the 2nd messengers, which then exert an effect within the cell.
Typically small molecules (often not proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis )
Inositol-1,4,5-trisphosphate ( IP3 IP3 Intracellular messenger formed by the action of phospholipase C on phosphatidylinositol 4, 5-bisphosphate, which is one of the phospholipids that make up the cell membrane. Inositol 1, 4, 5-trisphosphate is released into the cytoplasm where it releases calcium ions from internal stores within the cell’s endoplasmic reticulum. These calcium ions stimulate the activity of B kinase or calmodulin. Second Messengers )
cAMP cAMP An adenine nucleotide containing one phosphate group which is esterified to both the 3′- and 5′-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and acth. Phosphodiesterase Inhibitors
cGMP cGMP Guanosine cyclic 3. Phosphodiesterase Inhibitors
Ca CA Condylomata acuminata are a clinical manifestation of genital HPV infection. Condylomata acuminata are described as raised, pearly, flesh-colored, papular, cauliflower-like lesions seen in the anogenital region that may cause itching, pain, or bleeding. Condylomata Acuminata (Genital Warts) 2+
Hormone binding to its receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors → triggers conformational change within the receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors → triggers a reaction in the next protein in the cascade → triggers a reaction in the next protein, and so forth
Sequential Sequential Computed Tomography (CT) covalent modification of downstream proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis (often adding or removing phosphates to proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis )
Release of 2nd messengers
Altered gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics expression
Change of enzyme activities

Signaling via intracellular hormone receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors

Intracellular receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors generally cause direct gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics activation:

Steroid and thyroid Thyroid The thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck. Thyroid Gland: Anatomy hormones can diffuse directly into the cell.
Bind BIND Hyperbilirubinemia of the Newborn to intracellular receptors Receptors Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors
Hormone-receptor complexes bind BIND Hyperbilirubinemia of the Newborn directly to hormone response elements within the DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure .
Binding alters (typically stimulates) transcription Transcription Transcription of genetic information is the first step in gene expression. Transcription is the process by which DNA is used as a template to make mRNA. This process is divided into 3 stages: initiation, elongation, and termination. Stages of Transcription of target genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure → affects which proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis are being produced in the cell

Steroid hormone signaling

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37.2 How Hormones Work

Learning objectives.

Explain how hormones work
Discuss the role of different types of hormone receptors

Hormones mediate changes in target cells by binding to specific hormone receptors . In this way, even though hormones circulate throughout the body and come into contact with many different cell types, they only affect cells that possess the necessary receptors. Receptors for a specific hormone may be found on many different cells or may be limited to a small number of specialized cells. For example, thyroid hormones act on many different tissue types, stimulating metabolic activity throughout the body. Cells can have many receptors for the same hormone but often also possess receptors for different types of hormones. The number of receptors that respond to a hormone determines the cell’s sensitivity to that hormone, and the resulting cellular response. Additionally, the number of receptors that respond to a hormone can change over time, resulting in increased or decreased cell sensitivity. In up-regulation , the number of receptors increases in response to rising hormone levels, making the cell more sensitive to the hormone and allowing for more cellular activity. When the number of receptors decreases in response to rising hormone levels, called down-regulation , cellular activity is reduced.

Receptor binding alters cellular activity and results in an increase or decrease in normal body processes. Depending on the location of the protein receptor on the target cell and the chemical structure of the hormone, hormones can mediate changes directly by binding to intracellular hormone receptors and modulating gene transcription, or indirectly by binding to cell surface receptors and stimulating signaling pathways.

Intracellular Hormone Receptors

Lipid-derived (soluble) hormones such as steroid hormones diffuse across the membranes of the endocrine cell. Once outside the cell, they bind to transport proteins that keep them soluble in the bloodstream. At the target cell, the hormones are released from the carrier protein and diffuse across the lipid bilayer of the plasma membrane of cells. The steroid hormones pass through the plasma membrane of a target cell and adhere to intracellular receptors residing in the cytoplasm or in the nucleus. The cell signaling pathways induced by the steroid hormones regulate specific genes on the cell's DNA. The hormones and receptor complex act as transcription regulators by increasing or decreasing the synthesis of mRNA molecules of specific genes. This, in turn, determines the amount of corresponding protein that is synthesized by altering gene expression. This protein can be used either to change the structure of the cell or to produce enzymes that catalyze chemical reactions. In this way, the steroid hormone regulates specific cell processes as illustrated in Figure 37.5 .

Visual Connection

Art connection.

Heat shock proteins (HSP) are so named because they help refold misfolded proteins. In response to increased temperature (a “heat shock”), heat shock proteins are activated by release from the NR/HSP complex. At the same time, transcription of HSP genes is activated. Why do you think the cell responds to a heat shock by increasing the activity of proteins that help refold misfolded proteins?

Other lipid-soluble hormones that are not steroid hormones, such as vitamin D and thyroxine, have receptors located in the nucleus. The hormones diffuse across both the plasma membrane and the nuclear envelope, then bind to receptors in the nucleus. The hormone-receptor complex stimulates transcription of specific genes.

Plasma Membrane Hormone Receptors

Amino acid derived hormones and polypeptide hormones are not lipid-derived (lipid-soluble) and therefore cannot diffuse through the plasma membrane of cells. Lipid insoluble hormones bind to receptors on the outer surface of the plasma membrane, via plasma membrane hormone receptors . Unlike steroid hormones, lipid insoluble hormones do not directly affect the target cell because they cannot enter the cell and act directly on DNA. Binding of these hormones to a cell surface receptor results in activation of a signaling pathway; this triggers intracellular activity and carries out the specific effects associated with the hormone. In this way, nothing passes through the cell membrane; the hormone that binds at the surface remains at the surface of the cell while the intracellular product remains inside the cell. The hormone that initiates the signaling pathway is called a first messenger , which activates a second messenger in the cytoplasm, as illustrated in Figure 37.6 .

One very important second messenger is cyclic AMP (cAMP). When a hormone binds to its membrane receptor, a G-protein that is associated with the receptor is activated; G-proteins are proteins separate from receptors that are found in the cell membrane. When a hormone is not bound to the receptor, the G-protein is inactive and is bound to guanosine diphosphate, or GDP. When a hormone binds to the receptor, the G-protein is activated by binding guanosine triphosphate, or GTP, in place of GDP. After binding, GTP is hydrolysed by the G-protein into GDP and becomes inactive.

The activated G-protein in turn activates a membrane-bound enzyme called adenylyl cyclase . Adenylyl cyclase catalyzes the conversion of ATP to cAMP. cAMP, in turn, activates a group of proteins called protein kinases, which transfer a phosphate group from ATP to a substrate molecule in a process called phosphorylation. The phosphorylation of a substrate molecule changes its structural orientation, thereby activating it. These activated molecules can then mediate changes in cellular processes.

The effect of a hormone is amplified as the signaling pathway progresses. The binding of a hormone at a single receptor causes the activation of many G-proteins, which activates adenylyl cyclase. Each molecule of adenylyl cyclase then triggers the formation of many molecules of cAMP. Further amplification occurs as protein kinases, once activated by cAMP, can catalyze many reactions. In this way, a small amount of hormone can trigger the formation of a large amount of cellular product. To stop hormone activity, cAMP is deactivated by the cytoplasmic enzyme phosphodiesterase , or PDE. PDE is always present in the cell and breaks down cAMP to control hormone activity, preventing overproduction of cellular products.

The specific response of a cell to a lipid insoluble hormone depends on the type of receptors that are present on the cell membrane and the substrate molecules present in the cell cytoplasm. Cellular responses to hormone binding of a receptor include altering membrane permeability and metabolic pathways, stimulating synthesis of proteins and enzymes, and activating hormone release.

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StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

StatPearls [Internet].

Biochemistry, hormones.

Matthew B. McLaughlin ; Ishwarlal Jialal .

Affiliations

Last Update: July 17, 2023 .

Introduction

The endocrine hormones are a wide array of molecules that traverse the bloodstream to act on distant tissues, leading to alterations in metabolic functions within the body. They can broadly divide into peptides, steroids, and tyrosine derivatives that may work on either cell surface or intracellular receptors. A discussion on the synthesis, structures, and mechanisms of action of these hormones will follow.

Fundamentals

Peptide Hormones

The peptide hormones are water soluble molecules composed of amino acids (AA) linked by amide bonds. They exist as single polypeptide chains or as multimeric proteins, ranging in size from 3 to 200 AAs. They commonly derive from a single gene, with multimeric proteins being an exception. The peptide hormones act on cell surface receptors and therefore must be capable of exocytosis after translation. First, a ribosome translates a signal sequence that docks it to a signal recognition particle (SRP) on the rough endoplasmic reticulum (RER). Translation continues within the RER, and the growing peptide is cleaved from its signal sequence, forming a large preprohormone, which is cleaved to a prohormone, packaged in a vesicle, and sent to the Golgi apparatus. In the Golgi, peptides are cleaved into their final form and packaged into secretory vesicles that enter the cytoplasm. These vesicles undergo exocytosis upon cellular stimulus. Classic examples of this processing are pre-pro-PTH, pro-PTH and PTH as well as pre-pro-insulin, proinsulin, and insulin. The secretory vesicles often contain cleavage products in addition to the hormone as seen with insulin and C-peptide, which are co-secreted in equimolar concentrations. In addition to cleavages, other modifications occur in the RER and Golgi, namely N-linked and O-linked glycosylation of AA side chains. [1]

These hormones range broadly in size and structure, but several peptide families are of note. The glycoproteins are a group of heavily glycosylated alpha:beta heterodimers. The alpha-subunit is 92 AAs long and shared by all peptides of this class. This family includes thyroid-stimulating hormone (TSH) and the gonadotropins: follicle-stimulating hormone (FSH), luteinizing hormone (LH), and human chorionic gonadotropin (hCG). The POMC family consists of hormones derived from a single protein product that is cleaved at various lysine residues into multiple active peptides, including adrenocorticotropic hormone (ACTH) and beta-lipotropin. The posterior pituitary produces two peptide hormones that differ by only two AAs: oxytocin and anti-diuretic hormone (ADH). Both are nonapeptides with a disulfide bridge, which get packaged with carrier proteins called neurophysins. The Insulin/Insulin-like growth factor (IGF) family of hormones are peptides with three disulfide bonds. Insulin is a 51 AA hormone, consisting of two disulfide-linked polypeptide chains, while IGF-1 is a single polypeptide comprising 70 AAs. The growth hormone (GH) family are large, unglycosylated single polypeptide chains of approximately 200 AAs that have two internal disulfide bonds. This group includes GH, prolactin, and human placental lactogen.

Steroid Hormones

The steroid hormones are synthesized from cholesterol and are therefore lipophilic, freely diffuse across cell membranes, and have a structure of three contiguous cyclohexyl rings joined to one cyclopentyl ring. These cholesterol derivatives differ in their side groups and covalent bonds, which permits binding to different intracellular receptors. Steroid synthesis begins when the endocrine cell is stimulated by a peptide hormone, e.g., ACTH, leading to cleavage of stored cytoplasmic cholesterol esters and shuttling of newly-freed cholesterol to the mitochondria. The cholesterol side chain is then cleaved by cholesterol desmolase, forming pregnenolone; this is both the first committed step and the rate-limiting step (RLS) in steroid synthesis. Tissue-specific enzymes determine further transform pregnenolone to steroid end-products. Using the adrenal cortex as an example, zona glomerulosa cells form aldosterone via aldosterone synthase, zona fasciculata cells route pregnenolone towards cortisol formation via 17alpha-hydroxylase, and zona reticularis cells further route precursors towards sex steroid formation via 17,20 lyase. [2]

Tyrosine Derivatives

Within the chromaffin cells of the adrenal medulla, a single tyrosine molecule transforms into norepinephrine or epinephrine, water-soluble catecholamines that act as ligands for cell surface receptors. In the cytoplasm, tyrosine converts to dihydroxyphenylalanine (DOPA) via tyrosine hydroxylase, which is the RLS in catecholamine formation. DOPA then converts to dopamine via amino acid decarboxylase. Dopamine gets packaged into vesicles via vesicular monoamine transporter (VMAT) where it converts to norepinephrine via dopamine beta-hydroxylase. About 80% of the norepinephrine then transforms to epinephrine via phenylethanolamine-N-methyltransferase, whose activity is significantly increased by cortisol. Epinephrine and norepinephrine are exocytosed when these chromaffin cells undergo stimulation by acetylcholine acting at nicotinic cell surface receptors.

In the follicles of the thyroid gland, tyrosine converts into thyroid hormone (TH), a lipophilic polyiodinated dityrosine molecule that interacts with intracellular receptors. First, TSH stimulates iodide uptake along the basal surface of follicular cells via the sodium-iodide symporter. This transport is ATP-mediated and works against an electrochemical gradient, ensuring adequate iodide uptake. [3] Within the cell, hydrogen peroxide acts as an oxidizing agent to form iodine via the thyroid peroxidase (TPO) enzyme. Iodine is then actively transported across the apical surface to the lumen of the follicle where tyrosine residues lay attached to large thyroglobulin molecules. These residues are mono or diiodinated to form monoiodotyrosine (MIT) or diiodotyrosine (DIT). Adjacent MIT and DIT then conjugate to form either triiodinated or tetraiodinated dityrosine residues. Follicular thyroglobulin then gets endocytosed into the cell, where the endosome then fuses with a lysosome, leading to cleavage of these dityrosine residues from thyroglobulin, forming tetraiodinated thyroxine (T4) and triiodothyronine (T3), the more activate form of TH. TSH stimulates this process. Though lipophilic, TH is predominantly transported across the basal cell membrane rather than diffused; this is also true of cellular uptake. [4] However, its lipophilicity necessitates transport through the bloodstream via carrier proteins. These include thyroxine-binding globulin (70%), albumin (15 to 20%) and transthyretin (10 to 15%). Thyroid hormone is active when freely dissociated in the bloodstream, and its potency is further increased in the periphery when T4 converts to T3 via the enzyme 5’ deiodinase. [5]

Cell Surface Receptors

Many hydrophilic endocrine hormones act as ligands for G protein-coupled receptors (GPCR). These receptors characteristically have seven alpha-helical transmembrane domains, an N-terminus facing the extracellular space, and linkage to an intracellular trimeric G protein, consisting of alpha, beta, and gamma subunits. GPCRs allow for the signal of a ligand to be amplified many times over via intracellular second messenger systems. Once a ligand binds the extracellular domain of the GPCR, a there is the induction of a conformational change that releases the G protein into the cytoplasm. The subsequent second messenger system depends on whether the alpha subunit of the G protein is a G or G subtype. G subunits exchange a GDP molecule for GTP, causing it to dissociate from the trimeric complex. The alpha subunit then binds to the enzyme adenylyl cyclase, which converts ATP to cyclic AMP (cAMP). Two cAMP molecules then bind and activate protein kinase A (PKA). PKA is a kinase that specifically phosphorylates serine and threonine AA residues [6] . G subunits activate phospholipase C (PLC), a membrane-associated enzyme, with the assistance of the beta subunit. PLC then cleaves phosphatidylinositol 4,5-bisphosphate (PIP2), a membrane phospholipid, into diacylglycerol (DAG) and 1,4,5-triphosphate (IP3). IP3 freely associates with the cytoplasm while DAG remains membrane-bound. DAG then activates protein kinase C (PKC), which is also a serine-threonine kinase (19212139). Though the G and G receptors lead to the cAMP and DAG/IP3 pathways, respectively, the net effect of both is activation of intracellular serine/threonine kinases via second messengers, leading to altered activity of cytosolic enzymes and nuclear transcription factors. Common hormones that are mediated by G subunits include ADH, growth hormone-releasing hormone(GHRH), corticotropin-releasing hormone (CRH), ACTH, glycoproteins, gonadotropin-releasing hormone (GnRH), parathyroid hormone (PTH), calcitonin, and glucagon. Common hormones that are mediated by G subunits include thyrotropin-releasing hormone (TRH), GnRH, TSH, and PTH. Catecholamines act via both mechanisms.

The next major cell surface receptor is the insulin/IGF receptor, which has intrinsic tyrosine kinase activity. It is composed of alpha and beta chains and exists as either hetero or homodimers depending on how these chains combine. Signal transduction initiates when insulin or IGF binds the IR domain of the receptor, leading to a conformational change that causes autophosphorylation of tyrosine residues. Phosphorylation leads to recruitment of “adapter” proteins, names insulin receptor substrate (IRS) proteins and the SH2-B protein. These recruited proteins induce further downstream signaling of multiple pathways, including the MEK-MAPK pathway [7] . The net effect is the insertion of membranous GLUT4 channels and glucose transport and activation of enzymes that promote glycolysis and anabolism.

The tyrosine kinase-associated receptors also warrant mention. Like insulin/IGF receptors, they transduce signals via tyrosine kinases. Instead, a ligand causes conformational changes in the receptor that lead to activation of associated intracellular tyrosine kinases. The method by which these receptors activate tyrosine kinases is variable, though the JAK/STAT pathway is a typical example. In the JAK/STAT pathway, binding of the hormone leads causes receptor dimerization. These dimers activate Janus kinase (JAK) which reciprocally phosphorylates the receptor. STAT proteins then bind to these phosphate groups and subsequently dimerize with each other. The STAT dimers relocate to the nucleus and modulate gene transcription. Hormones that act as ligands for tyrosine kinase-associated receptors include GH, prolactin, and insulin. [8] [9]

Intracellular Receptors

All steroid hormone receptors act as transcription factors. Their general structure is a 6-domain single polypeptide chain consisting of regions “A” through “F.” The A and B domains exist near the amino terminus and are variable. The C domain is highly conserved across steroid receptor types, containing two zinc fingers that allow for binding within the DNA double helix at sites known as hormone response elements (HRE). The C region has small variances in the AA sequence to allow for differential transcriptional activity. The D domain is a hinge region, while the E domain is where steroid hormones bind to the receptor. The F domain is the carboxy-terminal, where a heat shock protein (HSP) is bound while the receptor is deactivated. When the steroid ligand binds to the E domain, the HSP gets released from the F domain. The F domain is now freely available for dimerization with an identical receptor; this homodimer transports to the nucleus, binds to an HRE, and modulates transcription. [10]

Like the steroid hormone receptors, the TH receptors also act as transcription factors. There are four types of TH receptors derived from alternative splicing of two different genes. They are single polypeptides with three functional domains: 1) a transcription factor-associated domain at the N-terminus, 2) a DNA binding domain with zinc fingers, and 3) a ligand-binding domain at the C-terminus. Unlike steroid hormone receptors, the predominant thyroid hormone receptor, TR-alpha1, exists in the nuclear envelope regardless of whether it is bound to a ligand. When highly active T transports across the target cell membrane, it binds the receptor, which then relocates to an HRE either as a monomer, homodimer, or as a heterodimer with the retinoid X receptor. The retinoid X heterodimer has the most transcriptional activity. [11]

Clinical laboratories can assay hormones relatively easily. Using automated immunoassay platforms, one can quantify most hormones with precision. In certain instances, such as urine free cortisol, the most reliable tests are high-performance liquid chromatography and mass spectrometry. In rare cases, techniques such as gel chromatography and equilibrium dialysis may be required to assay free hormones. However, clinical laboratories or reference laboratories can reliably measure most hormones.

Clinical Significance

Measuring serum and urine hormone levels can provide great insight when attempting to diagnose an endocrinological disorder, especially by cross-referencing multiple values. An example of this is the couple of TSH and T4. If TSH is undetectable and T4 and T3 show elevated, then the patient has primary hyperthyroidism, while if TSH measures elevated and T4 has decreased the patient has primary hypothyroidism. [12] Another coupling of anterior pituitary hormones and steroids is LH and testosterone. Elevated LH and testosterone in a young boy may suggest central precocious puberty. [13] Decreased LH and elevated testosterone in an adult male suggests exogenous testosterone use. The same concept applies to the pairing of PTH and calcium: when both PTH and calcium measure elevated, this suggests primary hyperparathyroidism while when both are low, it suggests primary hypoparathyroidism. [14] [15] However, when there is hypocalcemia with elevated PTH levels, it suggests a resistance syndrome due to a defect in receptor signaling, e.g., pseudohypoparathyroidism. Pairing insulin with C-peptide in the setting of fasting hypoglycemia will indicate to the clinician whether hyperinsulinemia is due to endogenous production (both elevated) or exogenous administration(hyperinsulinism, low C-peptide). Through careful ordering of tests and knowledge of basic hormone biochemistry, the clinician can identify the disease and initiate treatment.

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Disclosure: Matthew McLaughlin declares no relevant financial relationships with ineligible companies.

Disclosure: Ishwarlal Jialal declares no relevant financial relationships with ineligible companies.

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

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Hormones. Are one of the many ways our body’s cells “talk” to each other. Are produced by specialized glands (like ovaries, testes, thyroid and adrenals) Act like messengers to distant parts of the body. Neurotransmitters. N.T. also act as messengers in the body

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Hormones Are one of the many ways our body’s cells “talk” to each other. Are produced by specialized glands (like ovaries, testes, thyroid and adrenals) Act like messengers to distant parts of the body

Neurotransmitters • N.T. also act as messengers in the body • N.T. are chemicals that relay signals between nerve cells, or neurons. • Present throughout the body and are required for proper brain and body function, including hormone release. • N.T. imbalance = hormonal imbalance

Estrogens (estradiol, estrone, estriol) • Are hormones of growth and sexual development. • Develops and maintain female reproductive • Controls fluids and electrolyte balance. • Increases protein anabolism. • Keeps healthy breast tissue and skin

Estrogen Imbalances • Women: • High levels cause: • Weight gain, breast tenderness, heavy periods, increase risk of cancers • Low estrogen levels Cause: • Hot flashes, vaginal dryness and bone loss • Men: • High levels cause: • Prostate problems and reduced testosterone

Progesterone • Involved in reproduction • Nervous system health, and mood (feel-good hormone • Optimal levels balance and support other sex hormones (especially estrogen) • Activates gaba receptors-reducing N.t. activity important for people with pain, PMS, or compulsive disorders • Prepares uterus for implantation • Prepares mammary glands for lactation

Progesterone imbalances • Low levels: • Menopausal side effects • Hot flashes • Sleep disturbances • Irritability • In pregnancy can caused miscarriages • High levels: • Anti-estrogen

Estradiol • Most active of the estrogens • Functions: • Slows the breakdown of bone • Falls dramatically in menopause • Regenerates and preserves nerve cells in the brain. • Low levels linked to Alzheimer’s • Deficiency: cognitive/affective disorders • Mood disorders • Parkinson’s • Schizophrenia

Estriol • Weakest of estrogens, produced in ovaries • Production increases in pregnancy • Good indicator of fetal well-being and to predict pre-term labor • Anti-breast cancer effects

Neurotransmitters and hormones • N.T. can increase production of hormones • Seratonin increases output of hormones from the anterior pituitary • Seratonin increases prolactin levels---decreasing testosterone • Increases LH----increases testosterone in men, and estradiol in women • Increases (ACTH)---stimulates adrenals to increase cortisol levels

Estrogen/Progesterone metabolism • Synthesized in the ovaries from cholesterol via pregnenolone • Pregnenolone is precursor to DHEA and progesterone • Progesterone converts to cortisol in the adrenal glands • Adrenal also convert androstenedione to testosterone or to estrone • Testosterone is subsequently converted to estradiol via aromatase enzyme • Pregnenolone is significant in these pathways in that is the precursor to progesterone, estrogens and cortisol

Androgens (testosterone, DHEA, DHT) • Androgens help with the regeneration of skin, bones, and muscles • Low DHEA levels: • Fatigue, depressed, reduced mental function • DHT (dihydrotestosterone • Maintains lean muscle mass, and cardiovascular health in men and women • Low DHT levels: • Linked to low libido • Increase fat to lean muscle ratio • Coronary heart problems

Symptoms of estrogen dominance • Decreased libido • Cervical dysplasia • Depression, anxiety or agitation • Risk of endometrial cancer • Fat gain (especially around abdomen) • Fibrocystic breast and uterine fibroids • Thyroid dysfunction

Androgen disorders in women • Very common female disorder • Androgens from Greek word andros meaning masculine. • Symptoms appear gradually: • Irregular periods • Infertility • Weight gain more apple shape • Acne, hair loss and facial or chest hair

Liver function in hormone metabolism • Estrogenic hormones are detoxified and recycled in the liver • Via Phase I cytochrome p450 hydroxylation pathway • Fallowed by phase II glucorination, sulfation and methylation • Prolonged exposure of target tissue is a recognized risk factor of estrogen associated cancers.

Causes of menopausal symptoms • Hormonal fluctuations • Progesterone and estrogen levels decreasing • Stress • Negatively affects adrenal glands • Hypoglycemia • Low blood sugar levels will enhance menopausal symptoms • Poor diet and lack of exercise • Women who exercise regularly 4-5 times per week, were shown to have no signs of hot flashes. • Hypothyroidism • Liver dysfunction and biliary stasis • Inability to breakdown and detoxify estrogens

Environmental estrogens • Chemicals that behave like human estrogens • Scientific studies linked wild life reproductive disorders to chemicals from municipal waste, pesticides, which masquerade as hormones. • The use of plastics in food supply • Increase hormonal noise in our systems, causes our detoxification pathways to become jammed, creating physiological dysfunction • We need adequate detoxification to eliminate both exogenous and xenoestrogens in a regular basis to maintain health and balance.

DHEA and Cortisol • Regulates metabolism and body weight • Part of stress response system • Influence cognitive function • Affects neurotransmitter action • Norepinephrine, gaba and epinephrine • Cortisol potentiates gaba receptors • Reducing pain, anxiety and depression

Nutritional modulation of estrogen • Dietary fiber and lignins • Promotes proper excretion and reduced reabsorption • Reduces levels of free estradiol • Complex carbohydrates • Attenuates the glycemic and insulin index • Essential Fatty Acids • Decreases in c-16 Hydroxylation of estradiol • Protein • Inadequate protein may lead to decrease cytochrome P450 activity affecting hepatic detoxification pathways • Cruciferous vegetables • Indole-3-carbinol, isoflavones (soy and kudzu) • Folate, B2, B6, and B12 • Magnesium • Probiotics • Calcium D-glucarate

Detoxification of Xenoestrogens • Liver detoxification • Using specific nutrients to help Phase I & II • Making sure you have good glutathione reserves, proper absorption of B-complex to help this pathways. • Isoflovonoids • Healthy intestinal flora • Remove dietary antigens (allergens) • Dietary enzymes and HCL to improve digestion • Dietary supplements to regenerate GI track • Pantothenic acid, probiotics, minerals (zinc), L-glutamine, or L-carnitine • Dietary lignans from flax seeds to lower bioavailable levels of estrogen

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Topic summary contributed by volunteer(s): Linda

The consumption of animal products may cause an increase of the hormone, IGF-1 , which may increase both cancer risk and progression. Animal protein in particular may boost our IGF-1 production compared to plant proteins. The recent dramatic increase of hormone-dependent cancers in Japan has been speculatively linked to the steroids present in meat. Hormone replacement therapy (including bio-identical hormones ) has been shown to be associated with increased risk of heart disease , stroke, pulmonary embolism, and invasive breast cancer .

Hormones in meat may affect a woman’s fertility; eating a single serving of meat per day may increase infertility risk by 30%. Cooked meat contains PhIP , a heterocyclic amine that activates estrogen receptors almost as strongly as pure estrogen. Nettle tea and lavender may also have estrogenic effects. Early onset puberty in girls may be partly due to xenoestrogens (industrial pollutants often found in meat and fish ) and the hormones found in animal protein and milk . In contrast, eating soy may be associated with starting puberty 7-8 months later than girls who eat little or no soy. Mushrooms may also help prevent breast cancer by blocking estrogen production, thus decreasing the tumor’s ability to grow. All animal products contain estrogen. This may explain why, in a study of over a thousand women eating plant-based diets, vegan women had one-fifth the number of twins compared with vegetarians and omnivores.

Milk intake may be linked to increased prostate cancer risk and lower sperm counts in men. Endocrine-disrupting industrial toxins in the aquatic food chain may affect genital development of boys and sexual function in men. High rates of acne among milk drinkers may be associated with the high hormone levels in milk.

Steroid hormones, either naturally occurring or via synthetics (estrogen implants, animal feed, etc.), are unavoidable in food of animal origin. Trace amounts of hormones may be common in the environment and have been found in the water supply .

One way to decrease levels of steroid hormones in the body may be to avoid eggs , dairy, and meat. People on plant-based diets have lower levels of IGF-1 , which does not seem to affect their ability to accumulate muscle mass . Those on plant-based diets also have lower levels of adiponectin, a hormone that may contribute to cellulite. Those eating more plants hold onto more DHEA , an important hormone associated with increased longevity . A study confirmed that vegetarian women have lower levels of estradiol and therefore presumably a lower breast cancer risk due to higher fiber intake, which helps the body eliminate excess estrogen. Sex-hormone-binding globulins, which remove excess hormones from our bodies, have been found at higher levels in those eating vegetarian diets. Certain plant foods high in the hormone melatonin may help with insomnia .

For substantiation of any statements of fact from the peer-reviewed medical literature, please see the associated videos below.

Subscribe to our free newsletter and receive the preface of Dr. Greger’s upcoming book How Not to Age .

All Videos for Hormones

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24 - A Look Inside Hormone Health Studio For 2024, Plus A Cheeky Announcement‪.‬ Hormone Health Podcast

Alternative Health

Content Warning: this episode discusses pregnancy and pregnancy loss which may be triggering for some listeners. This short and sweet episode touches on a few exciting topics. Georgia has an announcement, we have an update on what's happening at Hormone Health Studio in 2024, and Chloe shares a third trimester pregnancy update. Thank you for joining us for another year of Hormone Health Podcast and following along on our work and personal journeys. We have so much planned for 2024 and, as always, we'd love to hear from you. Send us a DM on Instagram or email us at [email protected]

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How to Make a “Good” Presentation “Great”

Guy Kawasaki

Remember: Less is more.

A strong presentation is so much more than information pasted onto a series of slides with fancy backgrounds. Whether you’re pitching an idea, reporting market research, or sharing something else, a great presentation can give you a competitive advantage, and be a powerful tool when aiming to persuade, educate, or inspire others. Here are some unique elements that make a presentation stand out.

Fonts: Sans Serif fonts such as Helvetica or Arial are preferred for their clean lines, which make them easy to digest at various sizes and distances. Limit the number of font styles to two: one for headings and another for body text, to avoid visual confusion or distractions.
Colors: Colors can evoke emotions and highlight critical points, but their overuse can lead to a cluttered and confusing presentation. A limited palette of two to three main colors, complemented by a simple background, can help you draw attention to key elements without overwhelming the audience.
Pictures: Pictures can communicate complex ideas quickly and memorably but choosing the right images is key. Images or pictures should be big (perhaps 20-25% of the page), bold, and have a clear purpose that complements the slide’s text.
Layout: Don’t overcrowd your slides with too much information. When in doubt, adhere to the principle of simplicity, and aim for a clean and uncluttered layout with plenty of white space around text and images. Think phrases and bullets, not sentences.

As an intern or early career professional, chances are that you’ll be tasked with making or giving a presentation in the near future. Whether you’re pitching an idea, reporting market research, or sharing something else, a great presentation can give you a competitive advantage, and be a powerful tool when aiming to persuade, educate, or inspire others.

Guy Kawasaki is the chief evangelist at Canva and was the former chief evangelist at Apple. Guy is the author of 16 books including Think Remarkable : 9 Paths to Transform Your Life and Make a Difference.

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A person standing on asphalt road with gender symbols of male, female, bigender and transgender

Gender medicine ‘built on shaky foundations’, Cass review finds

Analysis finds most research underpinning clinical guidelines, hormone treatments and puberty blockers to be low quality

Review of gender services has major implications for mental health services

The head of the world’s largest review into children’s care has said that gender medicine is “built on shaky foundations”.

Dr Hilary Cass, the paediatrician commissioned to conduct a review of the services provided by the NHS to children and young people questioning their gender identity, said that while doctors tended to be cautious in implementing new findings in emerging areas of medicine, “quite the reverse happened in the field of gender care for children”.

Cass commissioned the University of York to conduct a series of analyses as part of her review.

Two papers examined the quality and development of current guidelines and recommendations for managing gender dysphoria in children and young people. Most of the 23 clinical guidelines reviewed were not independent or evidence based, the researchers found.

A third paper on puberty blockers found that of 50 studies, only one was of high quality.

Similarly, of 53 studies included in a fourth paper on the use of hormone treatment, only one was of sufficiently high quality, with little or only inconsistent evidence on key outcomes.

Here are the main findings of the reviews:

Clinical guidelines

Increasing numbers of children and young people experiencing gender dysphoria are being referred to specialist gender services. There are various guidelines outlining approaches to the clinical care of these children and adolescents.

In the first two papers, the York researchers examined the quality and development of published guidelines or clinical guidance containing recommendations for managing gender dysphoria in children and young people up to the age of 18.

They studied a total of 23 guidelines published in different countries between 1998 and 2022. All but two were published after 2010.

Most of them lacked “an independent and evidence-based approach and information about how recommendations were developed”, the researchers said.

Few guidelines were informed by a systematic review of empirical evidence and they lack transparency about how their recommendations were developed. Only two reported consulting directly with children and young people during their development, the York academics found.

“Healthcare services and professionals should take into account the poor quality and interrelated nature of published guidance to support the management of children and adolescents experiencing gender dysphoria/incongruence,” the researchers wrote.

Writing in the British Medical Journal (BMJ) , Cass said that while medicine was usually based on the pillars of integrating the best available research evidence with clinical expertise, and patient values and preferences, she “found that in gender medicine those pillars are built on shaky foundations”.

She said the World Professional Association of Transgender Healthcare (WPATH) had been “highly influential in directing international practice, although its guidelines were found by the University of York’s appraisal to lack developmental rigour and transparency”.

In the foreword to her report, Cass said while doctors tended to be cautious in implementing new findings “quite the reverse happened in the field of gender care for children”.

In one example, she said a single Dutch medical study, “suggesting puberty blockers may improve psychological wellbeing for a narrowly defined group of children with gender incongruence”, had formed the basis for their use to “spread at pace to other countries”. Subsequently, there was a “greater readiness to start masculinising/feminising hormones in mid-teens”.

She added: “Some practitioners abandoned normal clinical approaches to holistic assessment, which has meant that this group of young people have been exceptionalised compared to other young people with similarly complex presentations. They deserve very much better.”

Both papers repeatedly pointed to a key problem in this area of medicine: a dearth of good data.

She said: “Filling this knowledge gap would be of great help to the young people wanting to make informed choices about their treatment.”

Cass said the NHS should put in place a “full programme of research” looking at the characteristics, interventions and outcomes of every young person presenting to gender services, with consent routinely sought for enrolment in a research study that followed them into adulthood.

Gender medicine was “an area of remarkably weak evidence”, her review found, with study results also “exaggerated or misrepresented by people on all sides of the debate to support their viewpoint”.

Alongside a puberty blocker trial, which could be in place by December, there should be research into psychosocial interventions and the use of the masculinising and feminising hormones testosterone and oestrogen, the review found.

Hormone treatment

Many trans people who seek medical intervention in their transition opt to take hormones to masculinise or feminise their body, an approach that has been used in transgender adults for decades.

“It is a well-established practice that has transformed the lives of many transgender people,” the Cass review notes, adding that while these drugs are not without long-term problems and side-effects, for many they are dramatically outweighed by the benefits.

For birth-registered females, the approach means taking testosterone, which brings about changes including the growth of facial hair and a deepening of the voice, while for birth-registered males, it involves taking hormones including oestrogen to promote changes including the growth of breasts and an increase in body fat. Some of these changes may be irreversible.

However, in recent years a growing proportion of adolescents have begun taking these cross-sex, or gender-affirming, hormones, with the vast majority who are prescribed puberty blockers subsequently moving on to such medication.

This growing take-up among young people has led to questions over the impact of these hormones in areas ranging from mental health to sexual functioning and fertility.

Now researchers at the University of York have carried out a review of the evidence, comprising an analysis of 53 previously published studies, in an attempt to set out what is known – and what is not – about the risks, benefits and possible side-effects of such hormones on young people.

All but one study, which looked at side-effects, were rated of moderate or low quality, with the researchers finding limited evidence for the impact of such hormones on trans adolescents with respect to outcomes, including gender dysphoria and body satisfaction.

The researchers noted inconsistent findings around the impact of such hormones on growth, height, bone health and cardiometabolic effects, such as BMI and cholesterol markers. In addition, they found no study assessed fertility in birth-registered females, and only one looked at fertility in birth-registered males.

“These findings add to other systematic reviews in concluding there is insufficient and/or inconsistent evidence about the risks and benefits of hormone interventions in this population,” the authors write.

However, the review did find some evidence that masculinising or feminising hormones might help with psychological health in young trans people. An analysis of five studies in the area suggested hormone treatment may improve depression, anxiety and other aspects of mental health in adolescents after 12 months of treatment, with three of four studies reporting an improvement around suicidality and/or self-harm (one reported no change).

But unpicking the precise role of such hormones is difficult. “Most studies included adolescents who received puberty suppression, making it difficult to determine the effects of hormones alone,” the authors write, adding that robust research on psychological health with long-term follow-up was needed.

The Cass review has recommended NHS England should review the current policy on masculinising or feminising hormones, advising that while there should be the option to provide such drugs from age 16, extreme caution was recommended, and there should be a clear clinical rationale for not waiting until an individual reached 18.

Puberty blockers

Treatments to suppress puberty in adolescents became available through routine clinical practice in the UK a decade ago.

While the drugs have long been used to treat precocious puberty – when children start puberty at an extremely young age – they have only been used off-label in children with gender dysphoria or incongruence since the late 1990s. The rationale for giving puberty blockers, which originated in the Netherlands, was to buy thinking time for young people and improve their ability to smooth their transition in later life.

Data from gender clinics reported in the Cass review showed the vast majority of people who started puberty suppression went on to have masculinising or feminising hormones, suggesting that puberty blockers did not buy people time to think.

To understand the broader effects of puberty blockers, researchers at the University of York identified 50 papers that reported on the effects of the drugs in adolescents with gender dysphoria or incongruence. According to their systematic review, only one of these studies was high quality, with a further 25 papers regarded as moderate quality. The remaining 24 were deemed too weak to be included in the analysis.

Many of the reports looked at how well puberty was suppressed and the treatment’s side-effects, but fewer looked at whether the drugs had their intended benefits.

Of two studies that investigated gender dysphoria and body satisfaction, neither found a change after receiving puberty blockers. The York team found “very limited” evidence that puberty blockers improved mental health.

Overall, the researchers said “no conclusions” could be drawn about the impact on gender dysphoria, mental and psychosocial health or cognitive development, though there was some evidence bone health and height may be compromised during treatment.

Based on the York work, the Cass review finds that puberty blockers offer no obvious benefit in helping transgender males to help their transition in later life, particularly if the drugs do not lead to an increase in height in adult life. For transgender females, the benefits of stopping irreversible changes such as a deeper voice and facial hair have to be weighed up against the need for penile growth should the person opt for vaginoplasty, the creation of a vagina and vulva.

In March, NHS England announced that children with gender dysphoria would no longer receive puberty blockers as routine practice. Instead, their use will be confined to a trial that the Cass review says should form part of a broader research programme into the effects of masculinising and feminising hormones.

Transgender
Young people

More on this story

Veteran trans campaigner: ‘Cass review has potential for positive change’

Cass review must be used as ‘watershed moment’ for NHS gender services, says Streeting

‘This isn’t how good scientific debate happens’: academics on culture of fear in gender medicine research

Five thousand children with gender-related distress awaiting NHS care in England

Ban on children’s puberty blockers to be enforced in private sector in England

What Cass review says about surge in children seeking gender services

Adult transgender clinics in England face inquiry into patient care

‘Children are being used as a football’: Hilary Cass on her review of gender identity services

Thousands of children unsure of gender identity ‘let down by NHS’, report finds

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HORMONES. 2. The multiple activities of the cells, tissues, and organs of the body are coordinated by the interplay of several types of chemical messenger systems: 1. Neurotransmitters : released by axon terminals of neurons into the synaptic junctions and act locally to control nerve cell functions. 2.
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iii. Several important peptide hormones are secreted from the pituitary gland. The anterior pituitary secretes three: prolactin, which acts on the mammary gland; adrenocorticotropic hormone (ACTH), which acts on the adrenal cortex to regulate the secretion of glucocorticoids and growth hormone, which acts on bone, muscle, and the liver. iv.
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Premium Google Slides theme and PowerPoint template. This template will be your great ally to prepare your next lesson on hormones and endocrine glands for medical students. It has all the resources you need to convey the information clearly and be able to explain what hormones are, how the endocrine system works and which diseases affect it.
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Table: Major endocrine organs and their primary hormones; Gland/organ Hormone secreted by the gland/organ Primary effect of the hormone; Hypothalamus Hypothalamus The hypothalamus is a collection of various nuclei within the diencephalon in the center of the brain. The hypothalamus plays a vital role in endocrine regulation as the primary regulator of the pituitary gland, and it is the major ...
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An Image/Link below is provided (as is) to download presentation Download Policy: ... Hormones. Hormones. Topic B6. Production and function (B.6.1). primarily chemical messengers produced in endocrine glands secreted directly into bloodstream and transported to various organs, tissues, or cells in the body. have a variety of functions ...
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