Age-related changes in conversion of 5 alpha-androstan-17 beta-ol-3-one to 5 alpha-androstane-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol by rat testicular cells in vitro.

Conversion of labelled 5 alpha-androstane-17 beta-ol-3-one (DHT) by isolated testicular cells from rats of different ages was examined under saturating substrate conditions in vitro (5--10 micrograms DHT/ml in a 24 h incubation). Two detectable metabolites of DHT were produced by testicular cells in vitro. 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol) and 5 alpha-androstane-3 beta, 17 beta-diol (3 beta-diol). Production of these diols during a 24 h period was linear, and the amounts formed were directly related to the cell number. The amount of 3 alpha- and 3 beta-diols formed by testicular cells of rats of different ages increased from Day 10 to Day 25, then declined. Testicular cells from rats 10 to 20 days of age converted DHT mainly to 3 alpha-diol, but thereafter 3 beta-diol was the predominant testicular metabolite of DHT.