TRH's female repro phys; 3.31 Flashcards
Where are granulosa cells?
Around follicle…and antrum later on
What kind of receptor do granulosa cells have?
FSH receptor
What do granulosa cells produce?
Inhibin
Estrogen (estrone and estradiol-17β)
What is the downstream effect of inhibin?
Inhibits FSH secretion
What enzyme in granulosa cells form estrogen hormones?
CYP19 (aromatase)
Androstenedione → estrone (weak estrogen)
Testosterone → estradiol-17β (potent estrogen)
What is the downstream effect of estrogen on the HPO axis?
At low concentrations → suppresses secretion of FSH/LH
At high concentrations → stimulates secretion of FSH/LH
Where are theca cells?
Around granulosa cells
What kind of receptors do theca cells have?
LH receptors
LDL receptors
What do theca cells produce?
Androstenedione and some testosterone (goes to granulosa cells or vasculature)
What hypothalamic hormone stimulates secretion of FSH and LH?
Gonadotropin Releasing Hormone (GnRH)
What hypothalamic nucleus produces GnRH?
The arcuate nucleus produces GnRH
What kind of receptor does GnRH bind to?
Gq
hCG is released from where after fertilization of an egg?
Placenta
What is the effect of hCG?
hCG “rescues” the corpus luteum → keeps progesterone and estrogen levels high to maintain pregnancy
What else does the placenta do during pregnancy?
Takes over steroidogenesis and pregnancy maintenance
This is in regards to the menstrual cycle. What is the effect of the corpus luteum dying?
Corpus luteum dying → decreased estrogen and progesterone
This is in regards to the menstrual cycle. What is the effect of decreased estrogen and progesterone?
Decreased estrogen and progesterone → increased FSH/LH
decreased feedback inhibition
This is in regards to the menstrual cycle. What is the effect of increased FSH/LH?
Increased FSH/LH → gradually increased estrogen and growing/maturing follicles
(increases synthesis in granulosa cells)
This is in regards to the menstrual cycle. What is the effect of the gradual increase in estrogen?
Gradually increased estrogen → decreased FSH
feedback inhibition
This is in regards to the menstrual cycle. What is the effect of decreased FSH?
Decreased FSH → selection of largest/most FSH sensitive follicle
This is in regards to the menstrual cycle. What is the effect of selecting a single dominant follicle?
Single large follicle → produces HIGH levels of estrogen
This is in regards to the menstrual cycle. What is the effect of HIGH levels of estrogen?
HIGH levels of estrogen → stimulate secretion of FSH/LH
Inhibin is still inhibiting FSH secretion…so only LH is dramatically increased
This is in regards to the menstrual cycle. What is the effect of the LH surge?
LH surge → meiotic maturation, ovulation, and luteinization
This is in regards to the menstrual cycle. What is the effect of luteinization?
Luteinization → corpus luteum → HIGH levels of progesterone with some estrogen and inhibin
This is in regards to the menstrual cycle. What is the effect of HIGH levels of progesterone with some estrogen and inhibin?
HIGH levels of progesterone with some estrogen and inhibin → decreased FSH/LH
This is in regards to the menstrual cycle. What is the effect of decreased LH?
Decreased LH → corpus luteum dies
What can “rescue” the corpus luteum? (already on a card…but it fit here too)
hCG causes an increase in LH-like activity
What important hormonal shift induces parturition?
P > E → E > P
What effect does progesterone have on myometrial cells?
Hyperpolarization of myometrial cells → prevents contractions
What effect does progesterone have on adrenergic, oxytocin, and estrogen receptors?
Decreases/inhibits synthesis
What effect does progesterone have on prostaglandin?
Promotes storage of prostaglandin synthesizing enzymes
What effect does estrogen have on oxytocin receptors?
Estrogen increases oxytocin receptors
What effect does estrogen have on the uterus?
Estrogen promotes uterine contractility
What does estrogen do to the cervix?
Estrogen ripens the cervix
What effect does estrogen have on prostaglandin?
Increases local release → myometrial contractions
Which prostaglandins play major roles in reproduction?
PGF(2) and PHE
What effect do prostaglandins have on the antral (Graafian) follicle?
Involved in the rupture (release of the oocyte)
What role do prostaglandins play in the menstrual cycle?
Myometrial contraction during menstruation
What role do prostaglandins play in pregnancy/parturition?
Cause contactions (Braxton Hicks during pregnancy an strong uterine during parturition)
What develops during mammogenesis (breast development during puberty)
Epithelial ductal tree
What hormones are required for mammogenesis?
Estrogen, glucocorticoids, and GH (somatotropin)
When does lactogenesis I occur?
Mid/late pregnancy
What happens during lactogenesis I?
Lobular-alveolar growth
What hormones induce lactogenesis I?
Estrogen, glucocorticoids, prolactin, progesterone, and hPL
When does lactogenesis II occur?
Post-partum
What happens during lactogenesis II?
Onset of copious milk secretion
What induces lactogenesis II?
Decreased progesterone (parturition of the placenta)
What is galactopoiesis?
Maintenance of lactation
Presence of prolactin and removal of milk
What induces milk ejection (let-down)?
Oxytocin, anticipation, and suckling
What is involution?
Lack of prolactin
