Inhibition of septal hyperreactivity by testosterone and its reversion by an estrogen antagonist in weanling female rats

Abstract

Neonatal administration of testosterone inhibits emotional hyperreactivity to capture and tactile stimulation in female rats following septal lesions at 25 days of age. Testosterone, an aromatizable androgen, after metabolization to estrogen interacts with estrogen receptors in neonatal rat brain. In order to investigate whether the testosterone inhibited septal hyperreactivity via estrogen receptors rats were tested after pretreatment with the estrogen receptor antagonist tamoxifen. Weanling female rats pretreated with tamoxifen showed emotional hyperreactivity, while androgenized females showed no change. In addition, estradiol benzoate, neonatally administered, was able to inhibit emotional reactivity displayed after septal lesions. These results suggest that the action of testosterone on septal hyperreactivity might be mediated by estrogen receptors.