testostorone
What is testosterone?
Testosterone is produced by the gonads (by the Leydig cells in testes in men and by the ovaries in women), although small quantities are also produced by the adrenal glands in both sexes. It is an androgen, meaning that it stimulates the development of male characteristics.
Present in much greater levels in men than women, testosterone initiates the development of the male internal and external reproductive organs during foetal development and is essential for the production of sperm in adult life. This hormone also signals the body to make new blood cells, ensures that muscles and bones stay strong during and after puberty and enhances libido both in men and women. Testosterone is linked to many of the changes seen in boys during puberty (including an increase in height, body and pubic hair growth, enlargement of the penis, testes and prostate gland, and changes in sexual and aggressive behaviour). It also regulates the secretion of luteinising hormone and follicle stimulating hormone. To effect these changes, testosterone is often converted into another androgen called dihydrotestosterone.
In women, testosterone is produced by the ovaries and adrenal glands. The majority of testosterone produced in the ovary is converted to the principle female sex hormone, oestradiol.