5β-Reductase activity in the brain and cloacal gland of male and female embryos in the Japanese quail (Coturnix coturnix japonica)

Abstract

ABSTRACT Testosterone metabolism was studied by an in-vitro technique in the brain and cloacal gland of young male and female quail at different ages ranging from 7 days of incubation to 2 days after hatching. Very active metabolism, leading almost exclusively to the production of 5β-reduced compounds, was observed. 5β-Reductase activity remained high throughout the incubation period in the hypothalamus, decreased around the time of hatching in the cerebellum and decreased progressively between days 7 and 15 of incubation in the cloacal gland. These changes could be involved in the control of sexual differentiation: the high 5β-reductase in the brain possibly protects males from being behaviourally demasculinized by their endogenous testosterone while the decreasing 5β-reductase in the cloacal gland would progressively permit the masculinization of that structure. J. Endocr. (1984) 102, 77–81