Effect of Castration and Testosterone Substitution on the Urinary Output of Gamma-Glutamyl Transpeptidase and of N-Acetyl-Beta-D-GIucosaminidase of Male Rats with Renovascular Hypertension

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Abstract
The effect of castration of male rats with experimental renal hypertension (‘two kidney Goldblatt hypertension’) was studied on the height of the hypertension and on the urinary output of γ-glutamyl transpeptidase (γGT) and of N-acetyl-beta-D-glucosaminidase (NAG). Castration was carried out immediately after clamping one renal artery. Some of the castrates received testosterone substitution from the 3rd postoperative week onwards. Uncastrated hypertensive males served as controls. The experiments were carried out 8-18 weeks after eliciting high blood pressure. Hypertension as well as enzymuria were less expressed in castrates than in uncastrated males or in testosterone-substituted rats. In all animals studied the γGT excretion rate showed a positive correlation with the blood pressure. The output of γGT and of NAG as well as the specific γGT activity of the renal membrane fraction was lower in castrates than in uncastrated males or in substituted castrates. In uncastrated males and in testosterone-substituted castrates the daily NAG output showed a direct correlation with the renal hydroxyproline content. No such correlation was found in castrated males. The kidneys of castrates and of testosterone-substituted castrates contained less hydroxyproline than those of uncastrated males.