Explanation

$GnRH$ is secreted by the hypothalamus. It stimulates the anterior lobe of the pituitary gland to secrete LH and FSH. In male LH is known as Interstitial Cells Stimulating Hormone (ICSH) because it stimulates interstitial cells (Leydig’s cells) of the testes to secrete androgens. Testosterone is the principal androgen. FSH stimulates Sertoli cells of the testes to secrete an Androgen Binding Protein (ABP) that concentrates testosterone in the seminiferous tubules. Sertoli cells also secretes a protein hormone called inhibin, which suppresses FSH synthesis. FSH acts directly on spermatogonia to stimulate sperm production [image:3_image66.png]