Autoradiographic localization of ³H‐testosterone or its metabolites in the neonatal rat brain

The distribution of neurons which concentrate testosterone or its metabolites in the brain of 2‐day old female rats was determined using autoradiography. A specific topographic pattern of neurons which concentrate testosterone or its metabolites was obtained similar, but not identical, to the one found in adult male rats. The demonstrated sites of nuclear uptake and retention of testosterone or its metabolites by specific neurons in the neonatal brain probably provide the anatomical substrate for sexual differentiation of the brain.