Physiologic Course of Female Reproductive Function: A Molecular Look into the Prologue of Life

Figure 6

Evolution of the ovarian follicle and hormonal levels throughout the ovarian cycle. FSH: Follicle-Stimulating Hormone; GnRH: Gonadotropin-Releasing Hormone; LH: luteinizing hormone. Stricker et al. [151]. The first day of the ovarian cycle, GnRH levels commence a progressive rise, which is accompanied by FSH and, to a lesser extent, LH secretion. Ovarian stimulation by gonadotropins leads to a gradual increase in estradiol levels, which towards midcycle induce a LH peak. This LH acme triggers ovulation and thus begins formation of the corpus luteum. This tissue will then progressively achieve a peak in progesterone secretion and then gradually decline as gonadotropin levels drop and the corpus luteum degenerates into the corpus albicans, marking the end of the luteal phase, and the beginning of a new cycle.