Pituitary Hormones


Oxytocin polypeptide of 9 amino acids
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 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