Testosterone ELISA

Enzyme immunoassay for the quantitative determination of testosterone in human serum and plasma (EDTA, Citrate, Heparin). Testosterone, a C19-Steroid, is the most effective natural hormone in the family of androgens. Testosterone is the main male sex hormone and is secreted by the Leydig or interstitial cells of the testis. Small amounts of testosterone are secreted by the ovary and the adrenal, but about 50% of the testosterone production in women is derived from androstenedione by peripheral conversion. In the circulation, the main part of testosterone is bound to plasma proteins like sex hormone binding globuline (SHBG) and albumine. Only 1 - 2 % of the testosterone is unbound and therefore biologically active. Testosterone has a variety of actions in the body. In both sexes, it stimulates secondary sexual hair growth, alters the concentration of several enzymes of the kidney, stimulates erythropoiesis, and increases libido, competitiveness, and aggression. In men, it is responsible for the change in voice at puberty and promotes growth and development of the sex glands and organs. Testosterone in the male has a negative feedback on the hypothalamus and pituitary. Therefore, in men, high levels of testosterone are associated to the hypothalamic pituitary unit diseases. Increases in the secretion of the gonadotropins and testosterone, particularly during sleep, may indicate that puberty is progressing. Testosterone together with cortisol levels represents a useful parameter in stress research and sports medicine.