FORMATION OF 5α-REDUCED PRODUCTS FROM TESTOSTERONE IN VITRO BY GERM CELLS FROM IMMATURE RATS

Abstract

In the incubation study of [³H] testosterone with tissue homogenates in the presence of NADPH, it was shown that the rate of production of the sum of all 5α-reduced products by 30-day-old rat testes (50 to 100 nmoles/g tissue or 100 mg protein/h) was of the order of twenty times that by the ventral prostate (2 to 4 nmoles/g tissue/h). The activities of the C₁₉-steroid Δ⁴-5α-reductase of the seminiferous tubules, germ cells and tubular non-germ cells isolated from immature rats (7 to 10, 11 to 13 and 5 to 7 nmoles/100 mg protein/h, respectively) were of similar order to those of the prostate, while much less activity was found in the spleen and muscle. It was also noted that the activity of the 5α-androstane-3α-, and -3β-hydroxysteroid dehydrogenase seemed to be higher in each tissue of immature rat testes than in the prostate tissue. The seminiferous tubules were isolated by collagenase treatment and germ cells were separated from non-germ cells by tubular cell culture at 34°C for 2 days. Thus, germ cells of immature rat testes seem to have the characteristics of androgen responsive tissue.