Sheep anti-Methyldehydrotestosterone polyclonal antibody for EIA, IA, ELISA, WB, Dot, IHC. Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testicles of males and the ovaries of females, although small amounts are also secreted by the adrenal glands. It is the principal male sex hormone and an anabolic steroid.