In Part 1 of this article I introduced the endocrine system. The overview continues here. Following is a brief overview of the glands, the hormone(s) they produce, and the function of those hormones.
Future articles will provide more details.
Melatonin – sleep regulation, internal clock.
Produces several releasing hormones and inhibiting hormones. The releasing hormones stimulate the anterior pituitary to release hormones. The inhibiting hormones stop the anterior pituitary from secreting hormones. The major releasing hormones are:
Thyroid releasing hormone (TRH) – stimulates pituitary to release TSH.
Corticotropin releasing hormone (CRH) – stimulates pituitary to release ACTH.
Gonadotropin releasing hormone (GnRH) – stimulates pituitary to release FSH and LH.
The pituitary gland produces different hormones from its anterior and posterior parts.
The anterior pituitary secretes hormones to stimulate additional hormones. It receives its instructions from the hypothalamus.
Thyroid stimulating hormone (TSH) – stimulates secretion of thyroid hormones.
Adrenocorticotropic hormone (ACTH) - stimulates secretion of adrenal cortex hormones.
Follicle-stimulating hormone (FSH) – In females stimulates development of ovarian follicles and secretion of estrogen; in males stimulates testes to grow and produce sperm.
Luteinizing hormone (LH) – In females stimulates maturation of ovarian follicle and ovum; stimulates secretion of estrogen; triggers ovulation; and stimulates development of corpus luteum. In males stimulates interstitial cells of the testes to secrete testosterone.
Growth hormone (GH) - Stimulates growth in all organs; mobilizes food molecules, causing an increase in blood glucose concentration.
Prolactin (lactogenic hormone) - Stimulates breast development during pregnancy and milk secretion after pregnancy.
The posterior pituitary secretes ADH and oxytocin.
Antidiuretic hormone (ADH) - Stimulates retention of water by the kidneys.
Oxytocin - Stimulates uterine contractions at the end of pregnancy; stimulates the release of milk into the breast ducts; and plays a role in sexual arousal in males and non-nursing females (sometimes called the “cuddling hormone”).
Thyroxine (T4) and Triiodothyronine (T3) – Stimulate the energy metabolism of all cells.
Calcitonin – Inhibits the breakdown of bone; causes a decrease in blood calcium concentration.
Parathyroid hormone (PTH) – Stimulates the breakdown of bone; causes an increase in blood calcium concentration.
Thymosin – Promotes development of immune system cells.
Glucagon – Stimulates liver glycogenolysis, causing an increase in blood glucose concentration.
Insulin – Promotes glucose entry into all cells, causing a decrease in blood glucose concentration.
Mineralocorticoids: aldosterone – Regulates electrolyte and fluid homeostasis.
Glucocorticoids: cortisol (hydrocortisone) - Stimulates gluconeogenesis, causing an increase in blood glucose concentration; also have anti-inflammatory and anti-immunity, anti-allergy effects.
Sex hormones - the adrenals produce “female” hormones in males (estrogen, progesterone) and “male” hormones in females (testosterone).
Epinephrine (adrenaline) and norepinephrine - Prolong and intensify the sympathetic nervous response during stress.
Estrogen – Promotes development and maintenance of female sexual characteristics.
Progesterone – Promotes conditions required for pregnancy.
Testosterone – Promotes development and maintenance of male sexual characteristics.
Fat Storing Cells
Leptin – Controls how hungry or full we feel.