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Common Vertebrate Hormones




Pituitary Hormones


polypeptide of 9 amino acids CYIQNCPLG (C's are disulfide bonded)

uterine contraction, causes milk ejection in lactating females, responds to suckling reflex and estradiol, lowers steroid synthesis in testes

(antidiuretic hormone, ADH)

polypeptide of 9 amino acids CYFQNCPRG (C's are disulfide bonded)

responds to osmoreceptor which senses extracellular [Na+], blood pressure regulation, increases H2O readsorption from distal tubules in kidney

Melanocyte-stimulating hormones (MSH)

a polypeptide = 13 amino acids
b polypeptide = 18 amino acids
g polypeptide = 12 amino acids


Corticotropin (adrenocorticotropin, ACTH)

polypeptide = 39 amino acids

stimulates cells of adrenal gland to increase steroid synthesis and secretion

Lipotropin (LPH)

b polypeptide = 93 amino acids
g polypeptide = 60 amino acids

increases fatty acid release from adipocytes

Thyrotropin (thyroid-stimulating hormone, TSH)

2 proteins: a is 96 amino acids; b is 112

acts on thyroid follicle cells to stimulate throid hormone synthesis

Growth hormone (GH, or somatotropin)

protein of 191 amino acids

general anabolic stimulant, increases release of insulin-like growth factor-I (IGF-I), cell growth and bone sulfation

Prolactin (PRL)

protein of 197 amino acids

stimulates differentiation of secretory cells of mammary gland and stimulates milk synthesis

Luteinizing hormone (LH); human chorionic gonadotropin (hCG) is similar and produced in placenta

2 proteins: a is 96 amino acids; b is 121

increases ovarian progesterone synthesis, luteinization; acts on Leydig cells of testes to increase testosterone synthesis and release and increases interstitial cell development

Follicle-stimulating hormone (FSH)

2 proteins: a is 96 amino acids; b is 120

ovarian follicle development and ovulation, increases estrogen production; acts on Sertoli cells of semiferous tubule to increase spermatogenesis


Hypothalamic Hormones

Corticotropin-releasing factor (CRF or CRH)

protein of 41 amino acids

acts on corticotrope to release ACTH and b-endorphin (lipotropin)

Gonadotropin-releasing factor (GnRF or GnRH)

polypeptide of 10 amino acids

acts on gonadotrope to release LH and FSH

Prolactin-releasing factor (PRF)

this may be TRH

acts on lactotrope to release prolactin

Prolactin-release inhibiting factor (PIF)

may be derived from GnRH precursor, 56 amino acids

acts on lactotrope to inhibit prolactin release

Growth hormone-releasing factor (GRF or GRH)

protein of 40 and 44 amino acids

stimulates GH secretion

Somatostatin (SIF, also called growth hormone-release inhibiting factor, GIF)

polypeptide of 14 and 28 amino acids

inhibits GH and TSH secretion

Thyrotropin-releasing factor (TRH or TRF)

polypeptide of 3 amino acids: EHP

stimulates TSH and prolactin secretion


Thyroid Hormones

Thyroxine and triiodothyronine

iodinated dityrosin derivatives

responds to TSH and stimulates oxidations in many cells


protein of 32 amino acids

produced in parafollicular C cells of the thyroid, regulation of Ca2+ and Pi metabolism

Calcitonin gene-related peptide (CGRP)

protein of 37 amino acids, product of the calcitonin gene derived by alternative splicing of the precursor mRNA in the brain

acts as a vasodilator


Parathyroid Hormone

Parathyroid hormone (PTH)

protein of 84 amino acids

regulation of Ca2+ and Pi metabolism, stimulates bone resorption thus increasing serum [Ca2+], stimulates Pi secretion by kidneys


Hormones and Peptides of the Gut

additional dicussion of gastrointestinal hormones

Glucagon-like peptide 1
formerly called enteroglucagon

Two forms: 31 amino acids, GLP-1(7-37) and 30 amino acids, GLP-1(7-36)amide

potentiates glucose-dependent insulin secretion, inhibits glucagon secretion, inhibits gastric emptying

Glucose-dependent insulinotropic polypeptide
originally called gastric inhibitory polypeptide

polypeptide of 42 amino acids

inhibits secretion of gastric acid, enhances insulin secretion


28 amino acids; acylated and non-acylated forms found in circulation

appetite stimulation, regulation of energy homeostasis, glucose metabolism, gastric secretion and emptying, insulin secretion


23 amino acidsderived from pro-ghrelin protein,

acts in opposition to ghrelin action on appetite


17 amino acids

produced by stomach antrum, stimulates acid and pepsin secretion, also stimulates pancreatic secretions


27 amino acids

secreted from duodenum at pH values below 4.5, stimulates pancreatic acinar cells to release bicarbonate and H2O

Cholecystokinin, CCK

33 amino acids

stimulates gallbladder contraction and bile flow, increases secretion of digestive enzymes from pancreas


22 amino acids

controls gastrointestinal muscles

Vasoactive intestinal peptide (VIP)

28 amino acids

produced by hypothalamus and GI tract, relaxes the GI, inhibits acid and pepsin secretion, acts as a neurotransmitter in peripheral autonomic nervous system, increases secretion of H2O and electrolytes from pancreas and gut


14 amino acid version

inhibits release and action of numerous gut peptides, e.g. CKK, gastrin, secretin, motilin, GIP; also inhibits insulin and glucagon secretion from pancreas

Substance P
a member of the tachykinin family that includes neurokinin A (NKA) and neurokinin B (NKB)

11 amino acids

CNS function in pain (nociception), involved in vomit reflex, stimulates salivary secretions, induces vasodilation
antagonists have anti-depressant properties

PP, PYY and NPY constitute the Pancreatic Polypeptide family of 36 amino acid peptides.
PP and PYY exhibit endocrine functions.
NPY functions as a neuropeptide

Pancreatic Polypeptide, PP

36 amino acids

suppresses glucose-induced insulin secretion, inhibits bicarbonate and protein secretion from pancreas

Peptide Tyrosine Tyrosine, PYY

36 amino acids

inhibits gastric motility by inhibiting cholinergic neurotransmission, inhibits gastric acid secretion

Neuropeptide Tyrosine, NPY

36 amino acids
6 receptors

effects on hypothalamic function in appetite, controls feeding behavior and energy homeostasis, levels increase during starvation to induce food intake


2 peptides: 78 amino acid truncated form and 84 amino acid form with 6 additional N-terminal amino acids

homology to EGF and binds to the EGF receptor (EGFR)


Pancreatic Hormones


disulfide bonded dipeptide of 21 and 30 amino acids

produced by b-cells of the pancreas, increases glucose uptake and utilization, increases lipogenesis, general anabolic effects


polypeptide of 29 amino acids

produced by a-cells of the pancreas, increases lipid mobilization and glycogenolysis in order to increase blood glucose levels

Pancreatic polypeptide

polypeptide of 36 amino acids

increases glycogenolysis, regulation of gastrointestinal activity


14 amino acid version

inhibition of glucagon and somatotropin release


Placental Hormones



maintenance of pregnancy



mimic action of progesterone

Chorionic gonadotropin

2 proteins: a is 96 amino acids; b is 147

activity similar to LH

Placental lactogen

protein of 191 amino acids

acts like prolactin and GH


2 proteins of 22 and 32 amino acids

produced in ovarian corpus luteum, inhibits myometrial contractions, secretion increases durin gestation


Gonadal Hormones

Estrogens (ovarian)

steroids; estradiol and estrone

maturation and function of female secondary sex organs

Progestins (ovarian)

steroid; progesterone

implantation of ovum and maintenance of pregnancy

Androgens (testicular)

steroid; testosterone

maturation and function of male secondary sex organs

Inhibins A and B

1 protein (a is 134 amino acids; b is 115 and 116 amino acids

inhibition of FSH secretion


Adrenal Cortical Hormones


steroids; cortisol and corticosterone

diverse effects on inflammation and protein synthesis


steroids; aldosterone

maintenance of salt balance


Adrenal Medullary Hormones

Epinephrine (adrenalin)

derived from tyrosine

glycogenolysis, lipid mobilization, smooth muscle contraction, cardiac function

Norepinephrine (noradrenalin)

tyrosine derivative

lipid mobilization, arteriole contraction


Liver Hormones

Angiotensin II

polypeptide of 8 amino acids derived from angiotensinogen (present in the a2-globin fraction of plasma) which is cleaved by the kidney enzyme renin to give the decapeptide, angiotensin I, the C-terminal 2 amino acids are then released (by action of angiotensin-converting enzyme, ACE) to yield angiotensin II

responsible for essential hypertension through stimulated synthesis and release of aldosterone from adrenal cells


Kidney Hormones

[1,25-(OH)2-vitamin D3]

derived from 7-dehydrocholesterol

responsible for maintenance of calcium and phosphorous hoemostasis, increases intestinal Ca2+ uptake, regulates bone mineralization


Cardiac Hormones

Atrial natriuretic peptide (ANP)

several active peptides cleaved from a 126 amino acid precursor

released from heart atria in response to hypovolemia, acts on outer adrenal cells to decrease aldosterone production; smooth muscle relaxation


Pineal Hormones



regulation of circadian rhythms


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