REGULATION OF IMMUNOREACTIVE ANDROGEN RECEPTOR IN THE ADRENAL-GLAND OF THE ADULT-RAT

The androgen receptor (AR) was measured by an immunoblot assay in adul t tissues of both male and female rats. Relatively high levels of AR w ere detected in tissues of the male urogenital tract and in the adrena l glands and gonads of both sexes. Another group of tissues, including the male levator ani/bulbocavernosus muscles, preputial gland, scrota l skin, and vagina, had low, but detectable, levels of AR. In a third group of tissues, including the uterus, kidney, spleen, liver, gut, he art, lung, pituitary, and hypothalamus, AR was undetectable. In some a ndrogen target tissues, such as the penis, androgens cause an apparent disappearance of AR from the tissue, and in other tissues, such as th e ventral prostate, androgen therapy increases the amount of detectabl e AR. We compared the effect of androgen on AR levels in the adrenal g land and ventral prostate, tissues that differ markedly in their troph ic responses to androgen. Castration appeared to have no effect on the amount of detectable AR in the adrenal gland, whereas it caused a pro found decrease in AR levels in the ventral prostate. By contrast, 7 da ys after hypophysectomy, AR levels declined in both the adrenal gland and the ventral prostate. The effects of hypophysectomy plus castratio n were similar to those of hypophysectomy alone. Administration of ACT H to hypophysectomized rats for 7 days did not reverse the effects of hypophysectomy on adrenal AR, nor did treatment with levothyroxine, de xamethasone, rat GH, or rat PRL. Treatment of hypophysectomized rats w ith 5 alpha-dihydrotestosterone for 7 days caused a dramatic increase in the amount of detectable AR in both the ventral prostate and the ad renal gland, but had a trophic effect only in the ventral prostate. Th ese findings suggest that the amount of immunoreactive AR detected in both the adrenal gland and the ventral prostate is enhanced by androge ns: testicular androgens in the case of the ventral prostate and adren al androgen in the case of the adrenal glands.