Hormones — table
Source, actions and regulation of the body’s hormones. 47 entries.
Hypothalamic hormones 6
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Thyrotropin-releasing hormone (TRH) | Source: parvocellular neurons of the paraventricular nucleus → median eminence → portal blood. Targets: thyrotrophs (and lactotrophs) of the anterior pituitary. | Stimulates synthesis and release of TSH.; Stimulates prolactin release.; Acts as a neuromodulator elsewhere in the CNS. | Inhibited by T3/T4 (negative feedback), glucocorticoids and fasting; stimulated by cold, leptin (in the fed state) and the circadian system (TSH peaks at night). |
| Corticotropin-releasing hormone (CRH) | Source: parvocellular paraventricular neurons → median eminence (also placenta, limbic system). Target: corticotrophs of the anterior pituitary. | Stimulates ACTH (and other POMC peptides) secretion.; Coordinates central stress responses (arousal, sympathetic activation).; Inhibits GnRH secretion (stress-related amenorrhoea). | Stimulated by stress (pain, hypoglycaemia, hypotension, infection via IL-1/IL-6, fear) and the suprachiasmatic clock; inhibited by cortisol (negative feedback at hypothalamus and pituitary). |
| Gonadotropin-releasing hormone (GnRH) | Source: preoptic area and arcuate (infundibular) region → median eminence. Target: gonadotrophs of the anterior pituitary. | Stimulates synthesis and pulsatile release of LH and FSH.; Initiates and maintains puberty and reproductive function. | Stimulated by kisspeptin, adequate leptin/energy stores; inhibited by sex steroids (negative feedback, partly via KNDy neurons), progesterone (slows pulses), prolactin, CRH/cortisol, opioids and energy deficit.… |
| Growth hormone-releasing hormone (GHRH) | Source: arcuate (infundibular) nucleus → median eminence. Target: somatotrophs of the anterior pituitary. | Stimulates GH release and synthesis.; Promotes somatotroph proliferation.; Promotes slow-wave sleep. | Stimulated by hypoglycaemia, fasting, exercise, sleep, stress, α2-adrenergic agonists; inhibited by GH and IGF-1 (short- and long-loop feedback) and by somatostatin. |
| Somatostatin | Sources: periventricular nucleus of the hypothalamus; pancreatic δ cells; gastric and intestinal D cells; enteric neurons. Targets: somatotrophs and thyrotrophs; α and β cells; parietal, G and ECL cells;… | Inhibits GH and TSH secretion.; Inhibits insulin and glucagon release (paracrine).; Inhibits gastrin, gastric acid, pancreatic exocrine secretion, gallbladder contraction and nutrient absorption. | Hypothalamic release is stimulated by GH and IGF-1 (feedback); gastric D cells by luminal acid (pH <3) and gastrin; δ cells by glucose, amino acids and GLP-1. |
| Dopamine (prolactin-inhibiting hormone) | Source: arcuate nucleus (tuberoinfundibular dopaminergic neurons) → median eminence. Target: lactotrophs (D2 receptors). | Tonically inhibits prolactin secretion and lactotroph growth.; Mildly inhibits TSH secretion. | Stimulated by prolactin (short-loop feedback); inhibited by suckling, estrogen and stress. |
Anterior pituitary hormones 7
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Growth hormone (GH) | Source: somatotrophs of the anterior pituitary. Targets: liver (IGF-1 synthesis), growth plate chondrocytes, muscle, adipose tissue, bone. | Stimulates linear growth via IGF-1 at the epiphyseal plates (until fusion).; Increases protein synthesis and lean body mass.; Mobilises fat (lipolysis) and spares glucose; antagonises insulin. | Stimulated by GHRH, ghrelin, deep sleep, exercise, fasting, hypoglycaemia, amino acids (arginine), stress, sex steroids at puberty, α2-agonists (clonidine) and glucagon.… |
| Insulin-like growth factor 1 (IGF-1) | Source: liver (endocrine), plus chondrocytes, bone, muscle (paracrine/autocrine). Targets: almost all tissues, especially growth-plate chondrocytes, muscle and bone. | Mediates GH-dependent linear growth and anabolism.; Provides negative feedback on GH secretion.; Promotes cell survival and proliferation. | Increased by GH, insulin and adequate nutrition; reduced by malnutrition, liver disease, hypothyroidism and GH deficiency or resistance. Levels peak in puberty and fall with age. |
| Thyroid-stimulating hormone (TSH) | Source: thyrotrophs of the anterior pituitary. Target: thyroid follicular cells (TSH receptors also on orbital fibroblasts and adipocytes). | Stimulates iodide uptake, thyroglobulin iodination, coupling and T4/T3 release.; Stimulates growth and vascularity of the thyroid. | Stimulated by TRH; inhibited by T4/T3 (via local pituitary T4→T3 conversion), somatostatin, dopamine and glucocorticoids. |
| Adrenocorticotropic hormone (ACTH) | Source: corticotrophs of the anterior pituitary. Target: zona fasciculata and reticularis of the adrenal cortex (melanocytes at high levels). | Stimulates cortisol synthesis and secretion.; Stimulates adrenal androgen secretion.; Maintains adrenocortical growth (trophic). | Stimulated by CRH and ADH (V1b), stress, hypoglycaemia, circadian rhythm; inhibited by cortisol (fast and delayed negative feedback at pituitary and hypothalamus). |
| Follicle-stimulating hormone (FSH) | Source: gonadotrophs of the anterior pituitary. Targets: granulosa cells (ovary), Sertoli cells (testis). | Recruits and grows ovarian follicles; induces aromatase (estradiol synthesis) and LH receptors.; Stimulates Sertoli-cell function and spermatogenesis.; Stimulates inhibin secretion (which feeds back to suppress FSH). | Stimulated by slow-frequency GnRH pulses and activin; inhibited by inhibin B (selective), estradiol and testosterone. FSH rises when gonadal inhibin falls — the earliest marker of declining ovarian reserve. |
| Luteinizing hormone (LH) | Source: gonadotrophs of the anterior pituitary. Targets: Leydig cells (testis); theca cells, mature granulosa cells and corpus luteum (ovary). | Stimulates testosterone synthesis by Leydig cells.; Stimulates theca-cell androgen synthesis (estrogen precursor).; Mid-cycle surge triggers resumption of meiosis, ovulation and luteinisation. | Stimulated by fast-frequency GnRH pulses; inhibited by testosterone, estradiol and progesterone (negative feedback); sustained high estradiol produces positive feedback and the surge. |
| Prolactin (PRL) | Source: lactotrophs of the anterior pituitary (also decidua). Targets: mammary alveolar epithelium; hypothalamus (GnRH suppression). | Stimulates milk synthesis (lactogenesis and galactopoiesis).; Promotes breast development in pregnancy (with estrogen and progesterone).; Inhibits GnRH secretion (lactational amenorrhoea). | Inhibited by dopamine (D2) — dominant control. Stimulated by suckling, TRH, estrogen, pregnancy, sleep, stress, exercise, nipple stimulation, VIP and serotonin. Cleared by the kidney (raised in renal failure). |
Posterior pituitary hormones 2
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Antidiuretic hormone (ADH, vasopressin) | Source: magnocellular neurons of the supraoptic (mainly) and paraventricular nuclei; released from the posterior pituitary. Targets: collecting-duct principal cells (V2), vascular smooth muscle (V1a), corticotrophs (V1b). | Increases water reabsorption in the collecting ducts (concentrated urine, reduced plasma osmolality).; Constricts arterioles and raises blood pressure (V1a) in hypovolaemia.; Potentiates CRH-stimulated ACTH release. | Stimulated by raised plasma osmolality (OVLT osmoreceptors — most sensitive control), hypovolaemia/hypotension of ≥≈5–10 % (atrial and arterial baroreceptors — less sensitive but more powerful), angiotensin II, nausea and… |
| Oxytocin | Source: magnocellular neurons of the paraventricular (mainly) and supraoptic nuclei; released from the posterior pituitary. Targets: myometrium, mammary myoepithelial cells, brain. | Stimulates uterine contractions during labour and after delivery.; Causes milk ejection by contracting mammary myoepithelial cells.; Promotes maternal and social bonding behaviour. | Positive feedback: cervical/vaginal stretch (Ferguson reflex) and suckling (milk-ejection reflex). Inhibited by stress, pain, catecholamines and alcohol. |
Thyroid & calcium-regulating hormones 5
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Thyroxine (T4) | Source: thyroid follicular cells. Targets: nearly every tissue (after conversion to T3). | Serves as the circulating reservoir and prohormone for T3.; Mediates negative feedback on TSH and TRH (after local conversion to T3).; Indirectly (as T3) raises metabolic rate and drives growth and development. | TSH (TRH) stimulates secretion; free T4/T3 inhibit TSH and TRH. Iodide supply, deiodinase activity, binding-protein concentrations and drugs (amiodarone, lithium, iodinated contrast) alter levels. |
| Triiodothyronine (T3) | Source: thyroid follicular cells (≈20 %) and peripheral tissues by deiodination of T4 (≈80 %). Targets: nearly all tissues. | Raises basal metabolic rate, oxygen consumption and thermogenesis.; Increases heart rate, contractility and cardiac output; sensitises tissues to catecholamines.; Essential for CNS development and skeletal growth and maturation. | Generation of T3 is regulated tissue by tissue through deiodinases: fasting, critical illness, glucocorticoids, amiodarone, propranolol and propylthiouracil reduce T4→T3 conversion, while hypothyroidism up-regulates type 2… |
| Calcitonin | Source: parafollicular (C) cells of the thyroid. Targets: osteoclasts, kidney. | Inhibits osteoclastic bone resorption.; Increases renal calcium excretion.; Lowers plasma calcium (mildly and transiently). | Stimulated by hypercalcaemia (CaSR) and gastrin/pentagastrin; inhibited by low calcium. |
| Parathyroid hormone (PTH) | Source: chief cells of the parathyroid glands. Targets: kidney (proximal and distal tubules), bone (osteoblasts → osteoclasts); gut indirectly. | Raises plasma ionised calcium.; Lowers plasma phosphate (phosphaturia).; Stimulates calcitriol synthesis (increasing intestinal Ca²⁺ absorption). | Low ionised Ca²⁺ (CaSR) stimulates release (steep sigmoidal relationship); high Ca²⁺ and calcitriol inhibit secretion and synthesis; hyperphosphataemia stimulates; FGF-23 inhibits;… |
| Calcitriol (1,25-dihydroxyvitamin D₃) | Source: proximal tubule cells of the kidney (final step); precursors from skin and liver. Targets: small intestine, bone, kidney, parathyroid glands, immune cells. | Increases intestinal absorption of calcium and phosphate.; Enables normal mineralisation of bone matrix.; Enhances renal calcium reabsorption. | 1α-hydroxylase is stimulated by PTH, low phosphate and low calcium; inhibited by FGF-23, calcitriol itself (which also induces the inactivating 24-hydroxylase) and high phosphate.… |
Adrenal hormones 5
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Cortisol | Source: zona fasciculata of the adrenal cortex. Targets: virtually all cells (liver, muscle, adipose tissue, immune cells, vasculature, bone, brain). | Raises blood glucose by gluconeogenesis and insulin antagonism.; Mobilises amino acids and fatty acids.; Maintains vascular tone and blood pressure (permissive effect). | ACTH (from CRH and ADH) stimulates; cortisol inhibits CRH and ACTH. Circadian rhythm: peak in the early morning, around waking; nadir around midnight.… |
| Aldosterone | Source: zona glomerulosa of the adrenal cortex. Targets: principal and α-intercalated cells of the distal nephron; colon; sweat and salivary glands; heart and vessels. | Increases renal Na⁺ reabsorption (and so extracellular volume and blood pressure).; Increases K⁺ secretion — the main hormonal defence against hyperkalaemia.; Increases H⁺ secretion (acid excretion). | Stimulated by angiotensin II (AT1 — Gq), raised plasma K⁺ (direct depolarisation of glomerulosa cells; very sensitive) and, minimally, ACTH. Inhibited by ANP, hypokalaemia, heparin and dopamine.… |
| Adrenal androgens (DHEA, DHEA-S, androstenedione) | Source: zona reticularis of the adrenal cortex. Targets: peripheral tissues that convert them (skin, hair follicles, adipose tissue). | Drive adrenarche: pubic and axillary hair, apocrine body odour, sebum and acne.; Provide ≈50 % of circulating testosterone in women (via peripheral conversion) and contribute to libido.;… | ACTH (no negative feedback by androgens); age-dependent maturation of the zona reticularis. |
| Epinephrine (adrenaline) | Source: chromaffin cells of the adrenal medulla. Targets: heart, blood vessels, bronchial smooth muscle, liver, adipose tissue, skeletal muscle, pancreatic islets, eye. | Increases heart rate, contractility and cardiac output.; Redistributes blood to skeletal muscle and dilates the bronchi.; Raises blood glucose (glycogenolysis, gluconeogenesis, ↓insulin, ↑glucagon) and free fatty acids. | Released by sympathetic preganglionic activity triggered by exercise, hypoglycaemia (a powerful stimulus), hypotension/haemorrhage, cold, pain and emotional stress. Cortisol is required for its synthesis (PNMT induction). |
| Norepinephrine (noradrenaline) | Sources: postganglionic sympathetic nerve terminals (main) and adrenal medullary chromaffin cells (≈20 % of medullary output); also brainstem neurons (locus coeruleus).… | Maintains vascular tone and blood pressure (α1 vasoconstriction).; Increases myocardial contractility and (directly) heart rate (β1).; Stimulates lipolysis and renin release (β1). | Sympathetic nerve activity (baroreflex, posture, exercise, cold, stress); presynaptic α2 autoreceptors provide negative feedback on release. |
Kidney & cardiac hormones 4
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Renin | Source: juxtaglomerular cells of the afferent arteriole (juxtaglomerular apparatus). Substrate: plasma angiotensinogen (from the liver). | Cleaves angiotensinogen to angiotensin I, initiating the RAAS.; Thereby defends blood pressure, extracellular volume and GFR. | Stimulated by reduced renal perfusion pressure, low distal NaCl (macula densa), β1 sympathetic activity, loop diuretics and prostaglandins. Inhibited by angiotensin II, ANP, high NaCl, β-blockers and NSAIDs. |
| Angiotensin II | Formed in plasma, mainly in the lung by endothelial ACE, from renal renin acting on hepatic angiotensinogen. Targets: arterioles, adrenal cortex, hypothalamus, kidney, heart. | Vasoconstriction and increased blood pressure.; Stimulation of aldosterone, ADH and thirst.; Proximal tubular Na⁺ reabsorption and preservation of GFR (efferent constriction). | Formation is governed by renin secretion (rate-limiting); inhibits renin by short-loop feedback. |
| Erythropoietin (EPO) | Source: renal peritubular interstitial fibroblasts (≈90 %); liver (≈10 %). Target: erythroid progenitors (CFU-E, proerythroblasts) in red bone marrow. | Stimulates erythropoiesis to match oxygen-carrying capacity to tissue needs. | Stimulated by renal hypoxia — anaemia, low arterial P_O₂ (altitude, lung disease), increased haemoglobin O₂ affinity; androgens increase it. Rising red-cell mass closes the loop. |
| Atrial natriuretic peptide (ANP) | Source: atrial myocytes (ANP); ventricular myocytes (BNP). Targets: kidney, adrenal cortex, vascular smooth muscle, posterior pituitary. | Natriuresis and diuresis (increased GFR, reduced collecting-duct Na⁺ reabsorption).; Inhibition of renin, aldosterone and ADH.; Vasodilation and reduction of blood pressure and preload. | Stimulated by atrial (ANP) or ventricular (BNP) stretch, angiotensin II, endothelin and sympathetic stimulation; cleared by NPR-C and neprilysin. |
Pancreatic & incretin hormones 4
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Insulin | Source: β cells of the pancreatic islets. Targets: liver, skeletal muscle and adipose tissue (main); most tissues express receptors. | Lowers blood glucose: GLUT4-mediated uptake in muscle and fat; inhibition of hepatic glucose output.; Promotes storage of glycogen, triglyceride and protein (anabolic).; Inhibits lipolysis, ketogenesis and proteolysis. | Stimulated by glucose (main), amino acids (arginine, leucine), GLP-1 and GIP (incretins), glucagon, vagal stimulation (M3) and sulfonylureas.… |
| Glucagon | Source: α cells of the pancreatic islets. Targets: liver (main), kidney, adipose tissue, heart. | Raises blood glucose by glycogenolysis and gluconeogenesis.; Promotes hepatic fatty-acid oxidation and ketone body production.; Increases hepatic amino-acid uptake and urea production. | Stimulated by hypoglycaemia, amino acids (especially arginine, alanine), sympathetic activity and epinephrine (β2), exercise, stress and cortisol.… |
| Pancreatic polypeptide (PP) | Source: PP (F/γ) cells of islets in the head/uncinate process of the pancreas. Targets: exocrine pancreas, gallbladder, brainstem/hypothalamus. | Inhibits exocrine pancreatic secretion.; Relaxes the gallbladder.; Promotes satiety. | Stimulated by protein meals, fasting, exercise and hypoglycaemia via the vagus; abolished by vagotomy (the "sham-feeding PP test" assesses vagal integrity). |
| Glucagon-like peptide-1 (GLP-1) | Source: L cells of the ileum and colon (GIP: K cells of the duodenum/jejunum). Targets: β and α cells, stomach, brain. | Amplifies glucose-stimulated insulin secretion.; Suppresses glucagon secretion.; Slows gastric emptying. | Released by carbohydrate, fat and protein in the gut lumen; secretion is enhanced after bariatric surgery (rapid nutrient delivery to the distal gut). |
Pineal gland 1
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Melatonin | Source: pinealocytes of the pineal gland (smaller amounts in retina and gut). Targets: SCN, pars tuberalis of the pituitary, many peripheral tissues. | Signals the duration of darkness (internal "night").; Promotes sleep onset and lowers core temperature.; Phase-shifts and entrains circadian rhythms. | Darkness (via SCN → PVN → spinal cord → superior cervical ganglion → norepinephrine) stimulates; light suppresses. β-blockers reduce nocturnal melatonin. |
Gonadal & placental hormones 7
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Testosterone | Source: Leydig (interstitial) cells of the testis (also ovarian theca cells and adrenal precursors). Targets: reproductive tract, skeletal muscle, bone, skin, hair follicles, larynx, bone marrow, brain. | Fetal male differentiation (Wolffian ducts; with DHT, external genitalia and prostate).; Pubertal virilisation: genital growth, voice change, sexual hair, muscle mass, growth spurt.; Initiation and maintenance of spermatogenesis. | LH stimulates Leydig cells; testosterone (and its estradiol metabolite) inhibits GnRH and LH. FSH and inhibin B regulate the Sertoli side of the axis. |
| Estrogens (estradiol, estrone, estriol) | Source: ovarian granulosa cells (follicular phase) and corpus luteum; placenta (pregnancy); adipose tissue aromatisation (postmenopause and in men). Targets: uterus, cervix, vagina, breast, bone, brain, liver, blood vessels. | Development of female secondary sexual characteristics at puberty.; Proliferation of the endometrium; induction of progesterone receptors.; Positive feedback that triggers the LH surge and ovulation. | FSH (aromatase) and LH (theca androgen supply) stimulate ovarian synthesis; estradiol feeds back negatively on GnRH/FSH/LH except at mid-cycle (positive feedback). Placental estriol depends on fetal adrenal and liver function. |
| Progesterone | Source: corpus luteum (luteal phase, early pregnancy); placenta (after ≈7–9 weeks); adrenal cortex (as a precursor). Targets: endometrium, myometrium, cervix, breast, hypothalamus. | Converts proliferative to secretory endometrium; prepares for implantation and decidualisation.; Maintains pregnancy by suppressing myometrial contractility.; Thickens cervical mucus. | LH (luteal phase) and hCG (early pregnancy) stimulate the corpus luteum; placental production is largely autonomous. |
| Inhibin (and activin) | Source: granulosa cells, corpus luteum and placenta (inhibin A/B); Sertoli cells (inhibin B). Target: gonadotrophs of the anterior pituitary. | Selectively inhibits FSH secretion.; Acts locally within the gonad as a paracrine regulator. | FSH stimulates inhibin secretion (closing a negative-feedback loop); LH/hCG stimulates luteal and placental inhibin A. |
| Anti-Müllerian hormone (AMH) | Source: Sertoli cells (fetal and prepubertal testis); granulosa cells of small follicles (ovary). Targets: Müllerian ducts (fetus); ovarian follicles. | Regression of the Müllerian ducts in male embryos.; Regulation of follicle recruitment in the ovary. | Largely constitutive; in males suppressed by rising intratesticular testosterone at puberty; in females proportional to the number of small growing follicles. |
| Human chorionic gonadotropin (hCG) | Source: syncytiotrophoblast of the placenta (and some tumours). Targets: corpus luteum; fetal Leydig cells; maternal thyroid (weakly). | Maintains the corpus luteum and its progesterone secretion in early pregnancy.; Stimulates fetal testicular testosterone production.; Promotes placental angiogenesis and immunotolerance (local effects). | Production reflects trophoblast mass and is stimulated by GnRH-like signalling within the placenta; it is not under feedback control. |
| Human placental lactogen (hPL) | Source: syncytiotrophoblast. Targets: maternal adipose tissue, liver, muscle and breast. | Induces maternal insulin resistance and lipolysis, sparing glucose for the fetus.; Promotes breast development.; Stimulates maternal β-cell expansion. | Proportional to placental mass; increased by maternal hypoglycaemia and fasting. |
Gastrointestinal & adipose hormones 5
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Gastrin | Source: G cells of the gastric antrum and duodenum. Targets: ECL cells and parietal cells of the gastric body/fundus. | Stimulates gastric acid secretion (via histamine and directly).; Trophic effect on gastric mucosa.; Increases gastric motility. | Stimulated by peptides/amino acids, distension, vagal GRP, high antral pH; inhibited by antral acid (pH <3, via somatostatin), secretin and GIP. |
| Secretin | Source: S cells of the duodenal and proximal jejunal mucosa. Targets: pancreatic duct cells, bile duct epithelium, stomach. | Stimulates pancreatic and biliary bicarbonate secretion.; Inhibits gastric acid secretion and gastrin release.; Slows gastric emptying. | Released by duodenal acid (pH <≈4.5) and fatty acids; secretion falls once acid is neutralised. |
| Cholecystokinin (CCK) | Source: I cells of the duodenal and jejunal mucosa (also enteric and central neurons). Targets: gallbladder, sphincter of Oddi, pancreatic acini, stomach, vagal afferents. | Contracts the gallbladder and relaxes the sphincter of Oddi.; Stimulates pancreatic enzyme secretion.; Slows gastric emptying. | Stimulated by luminal fatty acids, monoglycerides, amino acids and peptides; released less when trypsin in the lumen degrades CCK-releasing peptides (feedback). |
| Ghrelin | Source: X/A-like (P/D1) cells of the gastric fundus and body. Targets: arcuate nucleus, somatotrophs, vagal afferents, stomach. | Stimulates appetite and meal initiation.; Stimulates GH secretion.; Increases gastric motility and acid secretion; promotes adiposity. | Rises with fasting, before meals and after weight loss; suppressed by food intake (especially carbohydrate), insulin and GH. |
| Leptin | Source: white adipocytes (also placenta, stomach). Targets: arcuate nucleus and other hypothalamic nuclei; GnRH network; immune cells; β cells. | Signals adequate energy stores; suppresses appetite.; Increases energy expenditure and sympathetic tone.; Permits puberty and fertility (via kisspeptin/GnRH). | Increased by fat mass, overfeeding, insulin and glucocorticoids; decreased by fasting, weight loss, catecholamines and cold. |
Thymic hormones 1
| Hormone | Source | Actions | Regulation |
|---|---|---|---|
| Thymosins and thymic hormones | Source: epithelial reticular cells of the thymus (anterior superior mediastinum). Targets: developing T lymphocytes (thymocytes) and peripheral T cells. | Promote T-cell differentiation and maturation.; Modulate immune responses. | Declines with age and thymic involution; reduced by glucocorticoids and zinc deficiency (thymulin). |