Sex Differences in Cytosolic Androgen Receptors in Gonadectomized Male and Female Rats

Abstract

The purpose of this experiment was to determine if there are sex differences in cytosolic androgen receptors (AR) in individual brain nuclei. Bilateral 500 μ diameter samples from 300 μ thick frozen brain sections were micropunched from males and females 2–3 weeks following gonadectomy. Tissue samples were taken from 12 brain nuclei: lateral septum, bed nucleus of the stria terminalis, medial preoptic nucleus, anterior hypothalamic area, arcuate nucleus, corticomedial nucleus of the amygdala, lateral preoptic area, parietal cortex, medial nucleus of the amygdala, dorsomedial nucleus of the hypothalamus, ventromedial nucleus of the hypothalamus, and dorsal hippocampus. Cytosolic ARs were higher in males than in females in each of these 12 areas, but this sex difference was significant only in the first 6. Sex differences in ARs were found in brain regions involved in the neuromodulation of androgen dependent responses. These data suggest that behavioral differences in male reproductive responses may be the result of a sexually dimorphic distribution of androgen receptor containing neurons.