What role does pituitary gonadotrophins play follicular and ovulatory phases of menstrual cycle and also explain the shift in steroidal secretions.

Explanation

Menstrual cycle is regulated by hypothalamus through the pituitary gland. At the end of menstrual phase, the pituitary FSH gradually increases resulting in follicular development within the ovaries. As the follicles mature, estrogen secretion increases resulting in a surge in (FSH and LH). The surge of LH is responsible for ovulation. LH also gonadotropins induce luteinisation which results in the formation of corpus luteum. Corpous luteum secretes progesterone and source estrogen which help in maintaining the interine endometrium for implantration.