Metabolism of androstenedione and 11-ketotestosterone in the kidney of the three-spined stickleback, Gasterosteus aculeatus

Stickleback kidneys were incubated with tritiated androstenedione (A4) or 11-ketotestosterone (OT). After the A4 incubations the following steroids were found, testosterone (T), 5β-androstane-3,17-dione (5βAd), etiocholanolone (Et), 5β-dihydrotestosterone (5βDHT), 5β-androstane-3α,17β-diol (5βA3α17βdiol), androsterone, 5α-androstane-3,17-dione, 5α-androstane-3α,17β-diol (5αA3α17βdiol), as well as glucuronides of T, Et, 5βDHT, 5βA3α17βdiol, and 5αA3α17βdiol. The metabolites found in the largest amounts were usually T, 5βAd, Et, and the glucuronides of T, Et, and especially of 5βA3α17βdiol. These results suggest the main pathway to be A4-5βAd-Et-5βA3α17βdiol-5βA3α17βdiol-glucuronide or Et-Et-glucuronide-5βA3α17βdiol-glucuronide. The formation of 5β-reduced compounds was larger in postbreeding males and females than in breeding males. The opposite was the case for 5α-reduced compounds. The total formation of glucuronides was lower in the breeding males than in the other groups. After the OT incubations 11-ketoandrostenedione, 17β-hydroxy-5β-androstane-3,11-dione (tentatively identified), and OT-glucuronide were found. 17β-Hydroxy-5α-androstane-3,11-dione was not present.