Abstract
In the preoptic area and the hypothalamus of rat brain, estrogen receptor (ER) α mRNA and protein are expressed and regulated by estrogen. Here we report sex difference and estrogen-dependent, region-specific regulation of ERβ, another major molecule which mediates estrogen action. ERβ mRNA and protein were visualized in the rat brain, in particular, the ventromedial nucleus of the hypothalamus, preoptic area and medial amygdala of both sexes, by either non-isotopic in situ hybridization or immunohistochemistry. In the ventromedial nucleus and the preoptic area of gonadectomized adult animals, a significantly larger number of neurons with ERβ message or protein were detected in females than in males. Such sex difference was not detected in the amygdala. In the ventromedial nucleus of either sex, estrogen administration to the gonadectomized adults caused a reduction of ERβ message or protein; no such effects were detected in the preoptic area or the amygdala. The results suggest that region-specific, ligand-dependent regulation of ERβ in the rat brain. [Jpn J Physiol 54 Suppl:S223 (2004)]
