Early androgen treatment and male sexual behavior in female rats

Abstract

Stimulation of the newborn male rat by endogenous testicular hormones and stimulation of the newborn female rat by exogenous testosterone will permanently suppress the rat's potential to respond to estrogen and progesterone with the display of feminine sexual behavior. Thus, early hormone stimulation de-feminizes the rat. Some data suggest that early testosterone stimulation may also enhance masculine sexual behavior and the reactivity of the adult rat to testosterone. Three experiments were conducted to evaluate this latter hypothesis. In Experiment 1 female rats were treated with oil at birth, with testosterone at birth, 96 hr after birth or 192 hr after birth. This postnatal testosterone stimulation did not increase the frequency of mounting behavior in response to testosterone treatment in adulthood. In Experiment 2 female rats were treated with testosterone or oil on Day 17 of gestation. This prenatal testosterone treatment did not increase the frequency of mounting behavior in response to testosterone treatment in adulthood. In Experiment 3 female rats were treated with testosterone or oil on Days 16–20 of gestation and 96 hr after birth. This prenatal and postnatal testosterone treatment did not increase the frequency of mounting behavior in response to testosterone treatment in adulthood. It was concluded that early testosterone stimulation does not enhance the rat's potential to display masculine sexual behavior or its reactivity to testosterone in adulthood.