Androgen receptors in the perinatal rat brain

Androgen receptors were identified and characterized in the cytosol and nuclear fractions of the perinatal female rat brain. Cytosol receptors have sedimentation coefficients in the range of 8 to 10S and bind to DNA cellulose columns. These receptors are detected in low concentrations in hypothalamus-preoptic area-amygdala-septum (HPAS) during the last few days of fetal life, less than 1/10th of levels found in adult HPAS. They undergo the most dramatic increase in concentration between postnatal days 7 and 15. Their appearance thus coincides temporally with the appearance of estrogen and progestin receptors, but the time course of their development is delayed, by comparison. Cell nuclear androgen receptors were also identified by gel exclusion chromatography and protamine sulfate precipitation after salt extraction of neonatal brain cell nuclei following in vivo labeling with both a synthetic and a natural androgen. Two well-known anti-androgens, cyproterone acetate and flutamide, are shown to inhibit the in vivo androgen binding to these cell nuclear receptors. The results are discussed in relation to androgen action in the perinatal rat brain, and the information currently available suggests that androgens influence both gonadotropin secretion and aspects of brain sexual differentiaton.