Reproductive endocrinology Flashcards
What are Leydig cells?
testis cells
what are sertioli cells?
testis cells
What do Leydig cells do?
form testosterone (lipid soluble - released as soon as it s made) LH activates enzymes- stimulate rate limiting step in production
What do Sertoli cells do?
receptor for FSH= expression of androgens receptor (AR)
testosterone binds= turn on androgen related gene producing enzyme (5aR)5a reductase
This enzyme reduces testosterone into dihydrotestosterone
How is dihydrotestosterone suited to its function ?
higher affinity than testosterone
needed for the production of male reproduction organs before birth
Whats does dihydrotestosterone and testosterone cause ?
spermatogenesis + masculinization
What does testosterone do (5)?
Increase muscle mass + bone density
Androgen effect Activates genes in Sertoli cells
drives mitosis of spermatogonial stem cells + meiosis entry
Lowers GnRH (hypothal) -ve feedback
Lower FSH + LH release from anterior pituitary -ve feedback
What are Thecal and Granulosa cells ?
Ovarian cells
Whats the most potent oestrogen
17 beta estradiol
what do Thecal cells do?
They’re LH receptors. When LH binds it turns on expression of cholesterol desmolase + 17-a-hydroxylase = produce androtestosterone + testosterone
Whats the function of Granulosa cells?
FSH receptor (converts Ando + testosterone into estrogen)
what does 17beta-estradiol do?
Stimulates:
- growth of uterus
- division of granulose cells in follicles
- granulosa cells to take up FSH receptor= more 17b-estradiol (+ve feedback)
- lowers GnRH
- lowers FSH +LH production from anterior pituitary
What causes ovulation?
Surge of LH
End of follicular phase due to sudden change in hypo to + feedback of GnRH release
What happens during ovulation?
Surge of LH
LH (+ FSH) increase
Dominant follicle ruptures
Release oocyte into reprod tract
Whats the hormone of pregnancy?
Progesterone
