What role does pituitary gonadotropins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions.

1. The two main pituitary gonadotropins are LH (luteinising hormone) and FSH (Follicle stimulating hormone). At the end of menstrual cycle, the amount of FSH increases that leads to the development of the follicles in the ovaries.

2. As follicles mature, oestrogen production increases. This in turn, increases the LH and FSH secretions.

3. The increased LH leads to ovulation and starts the formation of corpus luteum or luteinising.

4. Corpus luteum secretes progesterone and oestrogen which further maintains the endometrium lining.