[Hydroxylation of androgenic steroids in their target organs]

Enzymatic transformations of androgenic steroids in their target tissues lead to molecules which are androgenically more or less active than testosterone. Among such enzymes, and depending with organs, hydroxylases selectively act upon several androgenic steroids. In testes, the 7 alpha-hydroxylation of biosynthesized testosterone and androstenedione gives molecules implied in the regulation of male hormone production. In prostate, epididymis, sebaceous glands and pituitary, 6 alpha- and 7 alpha-hydroxylations only occur with 5 alpha-reduced and 3 beta-hydroxylated derivatives of 5 alpha-dihydrotestosterone. The cells preferentially dispose of such hydroxylated metabolites, but their formation is decreased by estradiol. The position of hydroxylations in the steroid hormone metabolism of each tissue is shown, and their implication in hormone-dependent pathologic growths are discussed.