FSH and LH
FSH and LH in Females and Males
FSH
LH
Female
stimulates ovary to produce steroids
ovary will produce estradiol during follicular phase and progesterone during luteal phase
surge at midcycle, with LH, triggers ovulation
stimulates ovary to produce steoroids
surge at midcycle triggers ovulation
remember, luteinizing hormone turns the follicle into the corpeus luteum by triggering ovulation
Male
stimulates Sertoli cells to produce androgen-binding protein (ABP), thereby stimulating spermatogenesis
FSH also stimulates Sertoli cells to produce inhibin, which provides negative feedback to the anterior pituitary to decrease FSH secretion
stimulates Leydig cells to produce testosterone
testosterone provides negative feedback to anterior pituitary and hypothalamus
In the female:
Estrogen:
Negative feedback:
occurs during follicular phases when estrogen levels are still low.
Postive feedback:
occurs at high concentrations near the end of the follicular phase, estrogen becomes a positive inducer of the anterior pituitary
positive feedback triggers the anterior pituitary to release more FSH and LH
more FSH and LH cause the ovary to produce more estrogen
the ensuing LH surge is responsible for ovulation
Progesterone:
stimulate secretory and vascular activity of the endometrium, preparing for implantation of an embryo
secreted by the corpus luteum, after ovulation
when corpus luteum regresses, progresterone levels fall
new vasculature in endometrium regresses and the tissue sloughs off.
