Androgen receptor immunoreactivity in intact and castrate guinea pig using antipeptide antibodies

We developed and used antibodies to an androgen receptor (AR)-specific synthetic peptide (amino acids 201-222 of the human androgen receptor) to localize AR in the brain and peripheral tissues of intact and castrate adult male guinea pigs. Immunoreactivity was localized to the nucleus of epithelial and stromal cells in the prostate of intact animals. Immunostaining was abolished in the prostate 4 days following castration. Androgen receptor immunoreactivity was found in brain nuclei known to be involved in reproductive and other androgen-dependent behaviors, including the preoptic area, medial basal hypothalamus, and anterior pituitary gland. Castration had no effect on the distribution or intensity of AR immunostaining in the brain. These data indicate a differential regulation of AR in the brain compared to peripheral tissues.