Androgens, natural sources

Infrared spectroscopy has been applied in identifying and determining the structures of steroids isolated from natural sources, for example, testis, ovary, placenta, adrenal cortex, bile, and blood. The technique has been used to identify compounds along the biosynthetic routes of, for example, cholesterol, pregnenolone, androgens, adrenal hormones, aldosterone, and estrogens. 

Ox bile, which contains cholic acid as its principal constituent, provided one of the earliest mammalian sources of steroid raw materials for the commercial manufacture of the androgens. In nature, cholesterol itself is the mammalian precursor of the androgens, the biosynthesis passing through progesterone (XII). 

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