Question | Answer |
homrones of the anterior lobe of the pituitary | TSH, LH, FSH/ ACTH,MSH/ growth hormone/ prolactin |
TSH,LH.FSH | belong to the same glycoprotein family, alpha subunits it identical while the beta subunit is responsible for activity of the hormone |
ACTH,MSH, beta-lipotropin, beta- endorphin | are derived from single prcurser, proopiomelanocortin. |
growth hormone ( somatortopin) | most important hormone for normal growth to adult size, is homologous to prolactin |
growth hormone | released in a pulsitile fassion; secretion is increased by sleep,stress,hormones related to puberty, starvation, excercise and hypoglycemia; secretion decreased by somatostatin, somatomedins, obesity, hyperglycemia, and prganancy |
GHRH | stimulates snthesis and secretion of growth hormone, somatostatin blocks it's effects, somatomedins produced by target hormones inhibits secretion by negative feedback |
Growth hormone | in the liver, generates somatomedins( IGF) [ IGF receptor uses tyrosine kinase |
growth hormone | decreases glucose uptake into cells, increases lipolysis, protein synthesis in muscle, increasing lean body mass, and increases the production of IGF |
actions of growth hormone via IGF | increases synthesis in chondrocytes and increases linear growth, increases protein synthesis in muscle and lean body mass, increases protien synthesis in most organs and organ size |
growth hormones dificiency | can be caused by lack of anterior pituitary growth hormone, hypothalamic dysfunction, failure to generate IGF in liver, growth hormone receptor deficiency |
growth hormone | excess causes acromegaly, can be treated with somatostatin analogs |
prolactin | responsible for lactogenesis, structurally homologous to GH |
prolactin | tonically inhibited by dopamine, thyrotropin releasing hormone increases it's secretion, inhibits it's own secretion by negative feedback |
prolactin | stimulates mild production, stimulates breast development along with estrogen, inhibits ovulation and spermogenisis |
hormones of the posterior pituitary | ADH and oxytocin, synthesized in hypothalamic nuclei and packaged with neurophysins, travels down nerve to post. pituitary |
ADH | originates primarily in supraoptic nuclei |
ADH | regulates serum osmolarity by increasing water permeability in late distal tubules and collecting ducts |
constricts vascular smooth muscle | ADH |
ADH | is increased by: increased serum osmolarity, volume contraction, pain, nausea, hypoglycemia, nicotine, opiates |
ADH | is decreased by: decreased serum osmolarity, ethanol, and alpha agonists |
oxytocin | originates in paraventricular nuclei |
oxytocin | causes ejection of milk from breasts as a result from the major stimulus of suckling |
oxytocin | dilates the cervix and is part of orgasm |
oxytocin | can be used to induce labor and reduce postpartum bleeding |