Androgen metabolism by rat epididymis. 4. The formation of conjugates.

The ability to form androgen conjugates and the hormone dependency of the conjugating enzymes have been studied in the rat epididymis. Following the in vitro incubation of 3H-testosterone with epididymal slices from intact and castrated rats, the radioactivity recovered was partitioned between water and ether. Examination of the water soluble radioactivity demonstrated the presence of glucuronides and sulfates. The total radioactivity in the conjugate fraction was the same for both intact and castrated animals. However, castrated rats showed a 3-fold increase in the glucuronide fraction with a corresponding decrease in the formation of sulfates. Characterization of the ether soluble radioactivity after solvolysis of the conjugate fraction from castrated animals, showed DHT (17beta-hydroxy-5alpha-androstan-3-one) and 3alpha-diol (5alpha-andro-stane-3alpha, 17beta-diol) to be the main metabolites. After beta-glucuronidase hydrolysis of the same, only 3alpha-diol could be demonstrated at a significant level, although traces of DHT and delta16 compounds were present. Corresponding hydrolysis of the water phase from incubation of epididymis from intact rats, demonstrated a marked quantitative difference. Here approximately 40% of the conjugated aglycones consisted of delta16 compounds, whilst only about 12% was comprised of 3alpha-diol. The preferential conjugation of DHT and 3alpha-diol to a sulfate radical was demonstrated in both intact and castrated rats. Since the conjugated delta16 compounds were detected only in the epididymis from intact animals, it is possible that these are formed by the spermatozoa.