Increased beta-adrenergic receptor complement in androgen-induced mouse kidney hypertrophy

Treatment of female mice with testosterone propionate led to a pronounced, but gradual increase in kidney beta-adrenergic receptor complement. The specific binding of [125I]iodohydroxybenzylpindolol rose 2-3-fold above the control levels after 8-12 days of the treatment. No significant changes were detected prior to the fourth day of androgen administration. No gross changes in either the binding strength or cooperativity of the binding were apparent in membrane preparations from treated animals. Averages of the high-affinity binding constant estimates were 1.3 +/- 0.3 nmol in controls, vs. 1.6 +/- 0.5 nmol in treated animals (15 groups each) in competition with pindolol, with the Hill slope factors of 0.98 +/- 0.08 for controls, and 0.91 +/- 0.07 for the treated animal membrane preparations. Scatchard estimates of the binding constants in self-competed [125I]iodohydroxybenzylpindolol binding were about 160 pmol in both control and treated animals. Competition experiments using isoproterenol also indicated similar dissociation constants (151 +/- 16 nmol) for control and treated groups. Na+/K+-activated ATPase (EC 3.6.1.3) was also found to be increased at the 12th day of the androgen treatment (to 74% above control levels).