SEX AND REGIONAL DIFFERENCES IN INTRACELLULAR-LOCALIZATION OF ESTROGEN-RECEPTOR IMMUNOREACTIVITY IN ADULT FERRET FOREBRAIN

Estrogen receptors were visualized in adult ferret brains using the H2 22 estrogen receptor antibody and immunocytochemical techniques. H222 immunoreactive (H222ir) cell nuclei were present in many forebrain reg ions in gonadectomized ferrets of both sexes. In many instances, H222i r cells also had immunoreaction product in their processes. All cells with H222ir processes also contained H222ir nuclei. More H222ir proces ses were observed in females in the medial and lateral preoptic area/a nterior hypothalamus, and at the level of the descending fornix and ca udal anterior commissure. Quantitative image analysis confirmed that f emales had significantly more (approximately 50%) extranuclear H222 im munoreaction product than males in cells in the magnocellular or preop tic subnuclei of the bed nucleus of the stria terminalis. Cells in the principal subnucleus of the bed nucleus of the stria terminalis and v entrolateral septum were notable for the relative paucity of H222ir pr ocesses. Sex differences in the intracellular extranuclear distributio n of estrogen receptor protein in particular brain regions might contr ibute to the differential regulation of estrogen-dependent functions i n the two sexes.