Gamete production is controlled by hormones in humans. The hypothalamus produces Gonadotrophin-releasing hormone (GnRH) which in turn stimulates the anterior pituitary gland to produce leutinizing hormone (LH) and follicle stimulating hormone (FSH). The hormones travel in the blood stream and stimulate testosterone production in the testes of males and oestrogen and progesterone production in the ovaries of females. The tesosterone stimulates sertoli cells in the male testes to promote spermatogenesis and oestrogen stimulates follicule development in female ovaries. These hormones produced in the gonads are also involved in a negative feedback loop, travelling via the bloodstream and inhibiting further production of GnRH by the hypothalamus and LH and FSH by the anterior pituitary.