The submicrosomal distribution in rat and boar testis of some enzymes involved in androgen and 16-androstene biosynthesis

The submicrosomal localization of enzymes involved in androgen and 16-androstene biosynthesis in rat and boar testis tissue has been studied. 16-Androstene production was not evident in the rat testis but two enzymes concerned with androgen generation (17α-hydroxy C₂₁ steroid C-17,20 lyase; 17β-hydroxysteroid dehydrogenase, were found predominantly in agranular microsomes.In the boar testis the C-17,20 lyase had a similar distribution to the rat enzyme but the 17β-hydroxysteroid dehydrogenase was found be evenly distributed between the two microsomal types. The enzyme system, “andien-β synthetase”, involved in the conversion of pregnenolone to 5,16-androstadien-3β-ol, was found mainly (66%) in the agranular microsomes but had a lower specific activity than those of the two enzymes of androgen biosynthesis that have been studied.