Gonadotropins (FSH & LH) and Reproductive Hormones

What hormone from the hypothalamus stimulates FSH and LH release?

GnRH (Gonadotropin-releasing hormone)

What is the main function of FSH in females?

Stimulates development of ovarian follicles.

Initiates folliculogenesis.

Stimulates release of estradiol and inhibin

What does FSH do in males?

Stimulates spermatogenesis.

Promotes inhibin secretion.

Stimulates Androgen-Binding Protein (ABP) synthesis in Sertoli cells

What does LH do in females?

Stimulates steroidogenesis (progesterone & estrogens).

Triggers ovulation.

Maintains corpus luteum

What does LH do in males?

Stimulates testosterone production in Leydig cells

Which hormone provides negative feedback on FSH?

Inhibin from Sertoli cells (males) or granulosa cells (females)

What causes the LH surge leading to ovulation?

Positive feedback from estradiol on the hypothalamus and pituitary (around day 13 of cycle)

When does FSH dominate the cycle? When does LH dominate?

• FSH: Follicular phase

• LH: Ovulation & luteal phase