Control in males

At the testis, LH stimulates Leydig cells to produce and secrete androgens, mainly testosterone. FSH, altogether with testosterone, acts on Sertoli cells to standardize the development of spermatozoa and secrete a glycoprotein, inhibin. The Gonadotrophin secretion in males is subject to negative feedback control by both of these secretions from the testis. Testosterone acts both at the hypothalamus, reducing the frequency of the episodic GnRH bursts, and at the anterior pituitary, building it less responsive to GnRH. Inhibin specially suppresses only FSH secretion and acts only at the anterior lobe. Humans have a circadian rhythm in testosterone secretion and women have modest cyclical changes in blood testosterone concentration, high about ovulation.