Androgen receptor messenger ribonucleic acid in brains and pituitaries of male rhesus monkeys: Studies on distribution, hormonal control, and relationship to luteinizing hormone secretion

Because the distribution and hormonal regulation of the androgen receptor ( AR) mRNA in brains and pituitaries of adult rhesus monkeys have not been st udied, we cloned and sequenced a 329-base pair segment of the 5' coding reg ion of the rhesus AR cDNA. Monkey AR cDNA was 99% identical with the human sequence and 96% homologous with the rat sequence. Using a ribonuclease pro tection assay, we studied the distribution and regulation of AR mRNA in bra ins and anterior pituitary glands of three groups of male rhesus monkeys: i ntact (n = 3), castrated (Cx, n = 4), and Cx treated with testosterone (n = 6). Serum testosterone levels of Cx males treated with testosterone differ ed significantly (p < 0.05) in the morning but not in the evening hours fro m those in intact controls. Serum LH concentrations were significantly supp ressed (p < 0.05) in both morning and evening serum samples of testosterone -treated males compared to intact controls. We found the highest concentrat ions of AR mRNA in the medial basal hypothalamus, the bed nucleus of the st ria terminalis, the medial preoptic area-anterior hypothalamus, and the lat eral dorsomedial hypothalamus. Intermediate amounts were found in the septu m and amygdala. Low amounts were found in the hippocampus, cingulate cortex , parietal cortex, and cerebellum. The anterior pituitary gland also contai ned a large amount of AR mRNA. Surprisingly, neither Cx for 3 wk nor Cx plu s testosterone replacement for 3 wk significantly affected AR mRNA in any b rain area or in the pituitary gland. The present study demonstrates that the effectiveness of testosterone as a regulator of LH secretion in male monkeys is not related to changes of AR m RNA in the brain or pituitary gland. It appears that AR mRNA in the monkey brain and pituitary gland is not regulated at the transcriptional level by androgen.