prolactin FA 01-16 Flashcards
Prolactin 2 functions?
lactogenesis and breast growth (with estrogen)
prolactin is structural homolog to what?
growth hormon
What inhibits prolactin synthesis?
dopamine
What activates prolactin synthesis?
TRH
How prolactine inhibits its release?
Promotes dopamine release from hypothalamus –> release of dopamine –> inhibits prolactin
Pregnancy (estrogen) on prolactin?
stimulates
breastfeeding on prolactin?
stimulates
Sleep on prolactin?
stimulates
stress on prolactin?
stimulates
TRH on prolactin?
stimulates
dopamine antagonists on prolactin?
stimulates
dopamine on prolactin?
inhibits
somatostatin on prolactin?
inhibits
dopamine agonists (bromocriptine) on prolactin?
inhibits
prolactin on prolactin?
inhibits (negative inhibition vie dopamine release)
what milk components are synthesized due to prolactin?
casein and lactose
prolactin effect on GnRH?
inhibits
what happens when prolactin inhibits GnRH?
decr FSH and LH –> decr. ovulation and spermatogenesis
insult to anterior pituitary –> what happens to prolactin?
decr. prolactin -> no lactation
How does destruction of the hypothalamus or interruption of the hypothalamic-hypophysial tract result in prolactin excess?
loss of inhibition by dopamine
why infertility when prolactin excess?
due to GnRH inhibition
galactorrhea, amenorhea, failure to ovulate, decr. libido, dec. spermatogenesis
Dopamine agonists?
bromocriptine
antipsichotics effect?
inhibits dopamine
dopamine antagonists?
most antipsychotics;
estrogen (OCPs, pregnancy)
THEY STIMULATE PROLACTIN PRODUCTION
nipple stimulation effect?
inhibits dopamine
OCPs/estrogen effect?
tiesiog stimulates production
koks dar weird dopamino inhibition mechanizmas?
Chest wall injury (via ANS)
Renal failure and prolactin?
Reduced prolatin elimination
primary or secondary hypothyroidism effect?
promotes TRH secretion -> incr. prolaction secr.
estradiol and progesterone on prolactin during preganacy?
block effect
UW. What prolactin level in prolactinoma?
> 200ng/ml
UW. if suspect prolactinoma, what other lab test need to do to differentiate?
rule out renal insuff (creatinine) and hypothyroidism (TSH, thyroixine)
UW. What size of prolactinoma does not cause mass symtoms?
is less than 1 cm. Do MRI
UW. Prolactinoma symptoms in premenopausal?
oligomenorrhea/amenorrhea, infertility, galactorrhea, hot flashes, decr. bone density
UW. Prolactinoma symptoms in ppostmenopausal?
mass effect symptoms (headache, visual defects)
UW. Prolactinoma symptoms in men?
infertility, decr. libido, impotence, gynecomastia (AKA HYPOGONADISM)
