TY - JOUR
T1 - Androgen receptor of rat penis is downregulated by androgen
AU - Takane, K. K.
AU - George, F. W.
AU - Wilson, J. D.
PY - 1990
Y1 - 1990
N2 - To provide insight into the factors that control androgen receptor levels in rat penis, we assessed 5α-[3H]-dihydrotestosterone binding in low-salt [10 mM tris(hydroxymethyl)aminomethane (Tris), 10 mM Na2M0O4] and high-salt (10 mM Tris, 10 mM Na2M0O4, 0.5 M KCl) extracts of rat penis using sucrose density gradients. Total receptor content decreased from ~ 729 ± 114 fmol/g tissue at 3 wk of age to < 50 fmol/g tissue at 10 wk of age. Castration of 3-wk-old rats prevented penile growth and the age-related decline in penile androgen receptor. Treatment of 3-wk-old castrated rats with 5α-dihydrotestosterone caused an acceleration in the decline in receptor levels compared with intact animals. Castration of 10-wk-old rats (after androgen receptor levels had decreased) did not result in an increase in the amount of total androgen receptor by 16 wk of age. To determine the specificity of the androgen-mediated decline in receptor levels, the amounts of prostate androgen receptor were compared with those of the penis at different ages. When expressed as femtomoles per organ, the total androgen receptor level in the prostate increased fourfold from 3 to 10 wk of age, whereas the total androgen receptor in the penis declined ~ threefold. We conclude that the downregulation of the penile androgen receptor content that occurs in the rat between 3 and 10 wk of age is androgen mediated, does not occur in all androgen target tissues, and is prevented but not reversed by castration.
AB - To provide insight into the factors that control androgen receptor levels in rat penis, we assessed 5α-[3H]-dihydrotestosterone binding in low-salt [10 mM tris(hydroxymethyl)aminomethane (Tris), 10 mM Na2M0O4] and high-salt (10 mM Tris, 10 mM Na2M0O4, 0.5 M KCl) extracts of rat penis using sucrose density gradients. Total receptor content decreased from ~ 729 ± 114 fmol/g tissue at 3 wk of age to < 50 fmol/g tissue at 10 wk of age. Castration of 3-wk-old rats prevented penile growth and the age-related decline in penile androgen receptor. Treatment of 3-wk-old castrated rats with 5α-dihydrotestosterone caused an acceleration in the decline in receptor levels compared with intact animals. Castration of 10-wk-old rats (after androgen receptor levels had decreased) did not result in an increase in the amount of total androgen receptor by 16 wk of age. To determine the specificity of the androgen-mediated decline in receptor levels, the amounts of prostate androgen receptor were compared with those of the penis at different ages. When expressed as femtomoles per organ, the total androgen receptor level in the prostate increased fourfold from 3 to 10 wk of age, whereas the total androgen receptor in the penis declined ~ threefold. We conclude that the downregulation of the penile androgen receptor content that occurs in the rat between 3 and 10 wk of age is androgen mediated, does not occur in all androgen target tissues, and is prevented but not reversed by castration.
KW - 5α-dihydrotestosterone binding
KW - growth
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U2 - 10.1152/ajpendo.1990.258.1.e46
DO - 10.1152/ajpendo.1990.258.1.e46
M3 - Article
C2 - 2301571
AN - SCOPUS:0025052060
SN - 0002-9513
VL - 258
SP - E46-E50
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 1 21-1
ER -