[Androgens and regression of the Mullerian ducts in the male mammalian embryo(author's transl)].

1. The capacity of androgen biosynthesis by the mouse embryo testis was studied in vitro. Testosterone and androstenedione were obtained from 14C-sodium acetate by testes undergoing sexual differentiation (12-12 1/2 days). 2. the question was examined whether testosterone or any other androgen could be regarded as the causative factor in the regression of the Mullerian ducts. Mullerian ducts from 13-14 - day - old mouse embryos were cultivated in vitro in the presence of a crystal of either testosterone, dihydrotestosterone or androsterone, but in none case could any regression be observed. Our conclusion tends to support the earlier view expressed by Jost (1970) and Josso (1970 beta) which holds that the regression of the Mullerian ducts in the male mammalian embryo is brought about by a factor different from androgens.