The Male Hormones
The hypothalamus produces Gonadotrophin releasing factors which stimulate the anterior pituitary gland to produce follicle stimulating hormones (FSH) and luteinising hormone (LH). The FSH act on the seminiferous tubule to bring about production of sperm, while LH acts on the interstitial cells (Leydig) within the testes, which produce testosterone. Testosterone is responsible for secondary sex characteristics - i.e. deepening of the voice, growth of the genitalia and growth of hair on the chest pubis, axilla and face, muscle mass development, strengthening of the bones and enlargement of the penis, scrotum, testes, prostate gland and seminal vesicle and all attribute to the influence of testosterone.