ABSTRACT
Estradiol exerts a negative feedback on FSH and LH secretion, mostly by acting at the level of hypothalamus. The relative weight of estradiol and inhibin in the regulation of central signaling to the gonads is roughly 50:50.19 The net effect of this network of hormone products is an early, rising FSH level that drives the recruitment of ovarian follicles. Estradiol and inhibin increase as a result of FSH stimulation. A dominant follicle is selected and inhibin A levels spike in concordance with the LH peak, signaling ovulation, and FSH levels fall. Estradiol production remains high and progesterone from the corpus luteum is elevated until the end of this phase of the menstrual cycle. In the absence of an ongoing pregnancy, the prepared endometrial lining sheds with the beginning of the subsequent cycle.
