Immunocytochemical localization of androgen receptors in brains of developing and adult male rhesus monkeys

We localized immunoreactive androgen receptors in the central nervous system (CNS) of fetal and adult male rhesus macaques by immunocytochemisty using an affinity-purified polyclonal antibody to the first 21 amino acids of the human androgen receptor (AR). This antibody caused a shift in the mobility of AR-bound ³H-DHT on a sucrose gradient and recognized a protein of approx 116 kDa on Western blot. Other criteria for specificity are presented. We localized AR in the diencephalon of male rhesus monkey fetuses. Immunoreactive neurons were found in the medial hypothalamic area and the ventromedial nucleus of the hypothalamus on days 47, 61, and 124 of gestation. At 124 d of gestation, AR immunoreactivity was also found in the arcuate nucleus. AR immunostaining was not found in other diencephalic structures in fetal life, including the preoptic area. In the adult monkey, neurons in ventromedial, dorsomedial, and arcuate nuclei of the hypothalamus; cortical, medial, and accessory basal nuclei of the amygdala; and regions of the hippocampus and the anterior pituitary gland contained immunoreactive AR. These data indicate that AR is found in specific areas of the CNS early in fetal development, but they also appear in other brain areas as the fetus grows. At 124 d of gestation (term, 167 d), the hypothalamic location of immunoreactive AR is similar to the adult.