In vitro conversion of 5α-reduced metabolites of testosterone by the seminal vesicles, ventral prostate glands and testes of adult rats

Abstract

In order to ascertain the ability of rat seminal vesicles, testes and ventral prostate glands to interconvert 5α-reduced androgens, these three organs were incubated with either tritiated 17β-hydroxy-5αandrostan-3-one (5α-dihydrotestosterone,DHT), 5α-androstane-3α, 17βdiol (3α-diol) or 5α-androstane-3β, 17β-diol (3β-diol). The incubation environment utilized (Krebs-Ringer bicarbonate glucose buffer) was selected because the histologic appearance of the tissue at the conclusion of the incubation was indistinguishable from tissue fixed immediately after sacrifice of the animal, thereby approximating the physiologic conditions as closely as possible. In incubations of rat seminal vesicles, 3H.-3β-diol was not metabolized while 26.7 ± 3.8% of 3H-3α-diol appeared as DHT and 17.2 ± 1.5% of 3H-DHT was metabolized to 3α-diol. A small amount (7.5 ± 0.8%) of 3H-DHT was, however, converted to 3β-diol. In incubations of rat testes, the major metabolite, regardless of substrate, was 3α-diol. The conversion of 75.7 ± 2.1% of 3H-3β-diol to 3α-diol has demonstrated, for the first time, that this steroid can be metabolized by the rat testis. Rat ventral prostate glands metabolized 18.5 ± 2.5% of 3H-3β- diol to DHT and 61± 2.9% of 3H-3α-diol to DHT. When 3H-DHT served as the substrate, 83.2 ± 1.5% remained unmetabolized. The prostate glands are, therefore, capable of metabolizing 3β-diol to DHT.