MOD 5 Flashcards
(47 cards)
What can pituitary growth do to vision?
pit tumor can compress optic chaism giving headaches and diplopia etc
Which pituitary (ant or post) makes its own hormones?
anterior! post just releases them
What does somatostatin inhibit
GH and TSH!
What does TRH stimulate?
TSH and PRL!
What gets converted to T3?
Free (unbound) T4!
What does LH do? FSH?
GnRH (pulsatile) in hypothal causes LH and FSH from ant pit. LH goes to Leydig cells in testes to make testosterone, and FSH goes to Sertoli cells in testes to make Inhibin B (and mature sperm)
In females, LH and FSH go to ovary and stimulate estriol and inhibin
What stim PRL?
TRH!
What does PRL inhib?
GnRH and thus FSH/LH (for inhibiting ovulation)
What drugs stim PRL secretion?
estrogens such as OCPs, and DA antags such as antipsychotics
What does PRL stim secretion of?
DA! DA inhibits PRL
What hormone does GH stim?
IGF-1 from liver! and SS!
What inhibits GH?
Somatostatin and IGF-1 (igf also inhib GHRH)
What does IGF-1 stim in hypothal?
SS! (igf stim SS which inhib GH)
What is the glucose tolerance test?
used to find cause of excess GH
give glucose which should inhib GH, if GH still high then there may be pit adenoma
post pit is made of?
SON (ADH) and
PVN (oxytocin, lactation and uterine contraction)
ADH receptors
V2- on basolateral memb of distal
V1 on SM regulates bp
most impt determinant of ADH release
plasma osmolality!
DI
central
nephrogenic
and tests
DI = DILUTE urine (cant conc urine)
- central: not making enough ADH
- nephrogenic- making adh but kidneys resistant to it
- dipsogenic DI is excess water drinking
- test with water deprivation test: if urine still dilute, is DI. if give desmopressin (DDAVP) and still dilute, its nephrogenic
Insulin tolerance test
-giving insulin to stim hypoglycemia
should cause increase in ACTH, cortisol and GH (these are diabetogenics)
Cushings disease vs syndrome
Acquired disorder of the pituitary
- Cushings Disease: pit ADENOMA making too much ACTH
- SYNDROME is just excess cortisol from adrenal glands making too much
Hyperprolactinemia vs Real Prolactinemia
Hyper- elev PRL due to drugs hypothy etc
Real- elev PRL due to pit adenoma!
what can elev PRL cause?
infertility, amenorrhea from neg feedback to pit (suppr LH and FSH), galactorrhea in women, irreg menstru, breast atrophy; in men may cause impotence, visual field abnormalities if large and affecting optic chiasm
Tx for elev PRL
bromocriptine or carbegoline (DA agonist) or surg
Dont eval PRL levels during….
preg! bc always high