Reproductive Lecture 5 Flashcards
What is Relaxin?
a hormone produced by corpus luteum/placenta in response to hCG
What does relaxin do?
inhibits myometrial contractions (ensures quiescence in early pregnancy)
relaxes pelvic bones and ligaments/softens cervix
What produces prolactin?
the pituitary (NOT the placenta)
What inhibits significant lactation?
high levels of progesterone and estrogen
What hormone stimulates growth of lactotrophs and increases PRL secretion?
estrogen
What hormones does the placenta produce (takes over from the corpus luteum)?
1) hCG
2) progesterone
3) HPL (HCS)
4) estrogen
Where is the major site of estrogen synthesis in the pregnant mom?
placenta (but it lack 17, 18 desmolase so cannot convert progesterone to androgens/estrogens)
uses androgenic substances from mom and baby (has limited ability to synthesis cholesterol and relies on maternal LDL as cholesterol source)
Where are fetal estrogens made?
fetal adrenal gland (20X larger)
What is the purpose of sulfating DHEA?
makes it more biosoluble (but less bioactive)
placenta removes sulfate and synthesizes estradiol and estrone
Which estrogen form is made only from fetal liver precursor?
estriol
What is responsible for hydroxylating DHEA-S in the 16 position?
fetal liver
16-OH-DHEA-S diffuses to placenta where sulfate group is removed and it is aromatized to __________
estriol
Go through the flow of estriol production
Cholesterol (from mom) —-> pregnenolone (placenta) —> pregnenolone (fetus) —-> DHEA —> DHEA-S —–> 16-OH DHEA-S —–> 16-OH DHEA-S —–> estriol
List some of the things progesterone does during pregnancy
1) inhibits prostaglandins/contractions
2) decreases sensitivity to oxytocin
3) inhibits maternal immune response to antigenic fetus
4) Mammogenesis - stimulates alveolar pouches of mammary glands, increases in capacity to secrete milk
What is the caveat to progesterone’s influence on lactogenesis?
high E2/progesterone prevents it
