Spermatogenesis is initiated at puberty by gonadotropin-releasing hormone (GnRH) released by the hypothalamus. GnRH stimulates the anterior pituitary to release gonadotropin hormones (LH and FSH). Follicle simulating hormone (FSH) initiates the production of sperm and causes release of inhibin. Luteinizing hormone (LH) stimulates production of testosterone by interstitial Leydig cells. Testosterone feedback inhibits production of LH and GnRH and is converted to dihydrotestosterone (DHT). DHT stimulates development of the external genitals.
The seminiferous tubules of the testis are the site of on-demand sperm development. Sertoli cells envelop and nourish developing sperm cells. They mediate actions of testosterone. Androgen-binding protein (ABP) produced by the Sertoli cells traps testosterone in the tubule lumen. Inhibin feedback inhibits the secretion of FSH.
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