Step F. Just before ovulation, estradiol rapidly rises from the dominant follicle and triggers LH surge by positive feedback; smaller FSH surge is caused by a rise in estradiol and activin (not shown) by positive feedback. Step G. LH surge causes ovulation 32-36 hours later. LH surge triggers meiotic maturation (Meiosis I, Prophase I to Meiosis II, Metaphase II). Step H. Rapid decline in LH and FSH due to pituitary exhaustion.
Menstrual Cycle: Hormonal Changes (III) Ovarian Cycle: Luteal Phase Step I . After ovulation, granulosa and thecal cells of dominant follicle transform anatomically and functionally into luteal cells under the influence LH; luteal cells secrete progesterone > estradiol (& inhibin). Step J. High progesterone, estradiol and inhibin suppress hypothalamic- pituitary axis, thus LH and FSH decline further during luteal phase suppressing follicular recruitment. Endometrial Cycle: Secretory Phase Progesterone causes endometrial maturation (glandular hypertrophy, secretions, embryo receptivity and pre-decidualization).