Brain cells of the male rhesus monkey accumulate 3 H‐testosterone or its metabolites

Autoradiography was used to localize target cells for 3 H‐testosterone or its labeled metabolites in the brain of the rhesus monkey. Two castrated males were injected intravenously with 3 H‐testosterone (2 mCi/monkey) and were killed 1 hour later. In both animals, neurons that concentrated radioactivity in their nuclei were located in a well‐circumscribed system that included the bed nucleus (n.) of the stria terminalis, medial preoptic n., suprachiasmatic preoptic n., anterior hypothalamic area, ventromedial hypothalamic n., cortical, medial, and basal accessory amygdaloid n., mesencephalic reticular n., and periaqueductal gray matter. In contrast to reports in some nonprimate mammalian species, little or no cellular labeling was observed in the lateral septum, arcuate n.‐median eminence, motor nuclei of cranial nerves, or spinal cord.