ANDROGEN AND ESTROGEN-RECEPTORS COEXIST WITHIN INDIVIDUAL NEURONS IN THE BRAIN OF THE SYRIAN-HAMSTER

Many aspects of reproductive neuroendocrine function and sexual behavi or are responsive to both androgens and estrogens, suggesting that rec eptors for these steroid hormones may reside within single cells in br ain regions that control reproductive function. We determined the dist ribution of estrogen receptor-containing neurons in 40-mu m coronal br ain sections in gonadectomized, DHT-treated male Syrian hamsters using immunocytochemistry with the H222 antibody (10 mu g/ml; Abbott Labora tories). Subsequently, we colocalized estrogen receptors with androgen receptors using the PG-21 antibody (0.5 mu g/ml; G.S. Prins). In male s, the distribution of estrogen receptor-containing neurons was simila r to that reported previously for the female hamster. Colocalization o f androgen and estrogen receptor immunoreactivity was observed in brai n regions that contain numerous androgen and estrogen receptor-positiv e neurons, including subdivisions of the medial preoptic area, bed nuc leus of the stria terminalis, ventromedial nucleus of the hypothalamus , and the amygdalohippocampal area. Single-labelled estrogen receptor- containing neurons were most numerous in the amygdalohippocampal area and the rostral medial preoptic nucleus; androgen receptor-immunoreact ive cells were most abundant in the ventral premammillary nucleus and the lateral septum. These data suggest the potential of androgens and estrogens to influence neuronal function within individual steroid rec eptor-containing neurons of the hamster limbic system.