Biotransformation of 4 [4-14C]4-androsteni-3,17-dione by healthy human skin in vitro.

The metabolism of [4-14C]4-androstene-3,17-dione was investigated in vitro with healthy female and male abdominal skin slices. With a reverse isotope dilution method the following androgenically active metabolites were isolated and identified:5 alpha-androstane-3,17-dione, androsterone, epiandrosterone, testosterone and 5 alpha-dihydrotestosterone. The quantitative relations of the metabolites produced revealed that the main direction of the metabolism of 4-androstene-3,17-dione in the healthy female and male abdominal skin segments is the 5 alpha-reduction of the delta 4-5 double bond. The other significant pathway is towards the biosynthesis of testosterone and 5 alpha-dihydrotestosterone. The importance of the androgenic steroids formed in the course of the biotransformation of 4-androstene-3, 17-dione in human skin is discussed.