The control of hypertension and its effect on renal function in rat remnant kidney

Blood pressure control and its influence on the rat remnant kidney function were studied. The deterioration in kidney function was followed for up to 20 weeks at 4-weekly intervals in four groups of 5/6th nephrectomised rats. The groups studied were: (1) Control, untreated (C), given normal rat chow containing 21% protein; (2) nisoldipine (a dihydropyridine calcium channel blocker) treated (N), given nisoldipine freshly mixed daily in normal chow (0.3-0.6 mg/kg body weight); (3) dihydralazine-treated (H), fed normal chow and given dihydralazine added daily to the drinking water, about 15-25 mg/kg body weight daily; and (4) low-protein (6%) diet (LP), isocaloric and having the same sodium content as the normal chow. Proteinuria, serum creatinine, blood urea, histological damage as seen by light microscopy, and cumulative survival were taken to assess the severity of the chronic renal failure. All three therapeutic regimens attenuated significantly the rise in blood pressure which developed within less than 4 weeks in the rats with the remnant kidney. At the 16th week, means +/- standard deviations were, in group C, 237 +/- 20 mmHg; group N, 147 +/- 20 mmHg; group H, 164 +/- 23 mmHg; and group LP 149 +/- 16. Systolic blood pressure at the 8th week had a significant correlation with the serum creatinine of the 12th and of the 16th weeks. There was a strong correlation between blood pressure and the serum creatinine at the 16th week. This indicates that a time lag is necessary for the hypertension to have an effect on kidney function. Proteinuria, serum creatinine and blood urea were much higher in the untreated group.(ABSTRACT TRUNCATED AT 250 WORDS)