growth hormone and prolactin Flashcards
prolactin
- where is it produced?
- free or bound?
- which receptor pathway?
produced in ant. pituitary
mostly free
needs to molecules bound to receptor to activate jak stat pathway
where does prolactin act?
what does it do there?
mammory gland
- lactogenesis
- galactogenesis
- mammogenesis
regulation of prolactin
dopamine tonically inhibits prolactin release
stimulated by TRH
function of estrogen and progesterone on mammory glandfs
increase mammogenesis, inhibit milk production
Prolactin hyperfunction
prolactotrope tumor
D2 receptor antagonism
-galactorhea, amenorrhea, loss of libido
increase of prolactin decreases GnRH
Prolactin Hypofunction
Sheehans syndrome–>hemmoraghic destruction of pituitary
-happens to a fraction of women giving birth
growth hormone
- where is it made?
- bound or free?
- which signaling pathway?
released from somatotrophs
essential for growth
significant portion bound to receptor fragments floating around in blood
activates Jak-Stat pathway
metabolic actions of GH
- increases glucagon, gluconeogenesis, glycogenolysis
- puts amino acids into muscle
- activates HSL lipolysis to increase free fatty acids
IGF
- what triggers its release?
- what signaling pathway?
- whats it cause?
triggered by growth hormone under normal levels of insulin
activates EGF receptors similar to insulin (IRS)
promotes long bone growth
promotes acquisitional growth
promotes muscle growth
GH regulation
- positives
- negatives
\+ hypoglycemia \+ amino acids (arginine) \+ GHRH - GH - Somatostatin
Hyper GH
Prepuberty- gigantism
-uncontrolled linear growth
increased IGF, increased GH, Diabetes
Post puberty- Acromegaly big hands and feet
Hypo
Larenge Dwarfism (GH receptor issue) African pigme (IGF receptor issue)
