Developmental changes in the rate of production of an unusual testosterone metabolite, 4-androstene-3 alpha, 17 beta-diol, by chick liver microsomes.

Testosterone is produced by the chick embryo testis from the 13th day of incubation. We have investigated the ability of microsomes prepared from the fetal and neonatal liver to metabolize testosterone and have found that the principal metabolite generated by microsomes in the presence of NADPH is 4-androstene-3 alpha, 17 beta-diol. The rate of production of this metabolite declined sharply over the time of hatching. Conversely, 16 alpha-hydroxytestosterone production increased transiently just after hatching. Our findings indicate that chick liver microsomes contain a 3 alpha-hydroxysteroid dehydrogenase (3 alpha-hydroxysteroid: NAD(P) oxidoreductase, EC 1.1.1.50) whose activity changes during development.