gonadotropin

Question 1

describe HPA axis of gonadotropin:

Answer 1

hypoth release GnRH > target gonadotrophs in ant pit > release LH + FSH: targer = ovaries/testes > release of estrogen/progesterone or testosterone
result: ovulation or spermatogenesis

Question 2

describe GnRH and its receptor

Answer 2

GnRH cleaved from larger precursor
- released frequency = constant male; female = varies with menstrual cycle
the receptors are GPCR> Gq > ^PLC > IP3 > increase intracel ca2+ > exocytosis of LH and FSH

Question 3

how does LH and FSH work in males

Answer 3

FSH acts on Sertoli cells > stimulate development of sperm
LH acts on Leydig cells in testes > secretes hormones like testosterone (negative feedback for FSH/LH/GnRH)

Question 4

describe what testosterone do

Answer 4

• negative feed back > inhibi release of GnRH LH and FSH
• growth of sexually dimorphic nucleus (in preoptic area) directed by testosterone -critical for sexual behavior
• increased level not correlated with sex drive past thresh hold

Question 5

how does LH and FSH work in females

Answer 5

FSH increases synthesis of estrogen and stimulates maturation of follicles in ovary; LH surge stimulates ovulation
Estradiol levels increase (priming) before progesterone levels begin to increase right before ovulation (sexual responsiveness)

Question 6

what happens with pituitary tumors

Answer 6

Pituitary tumors can lead to failure in gonadotrophs
Amenorrhea in females, impotence in males