Blood pressure and renal hemodynamics in hypertensive Cyp1a1‐Ren2 transgenic rats fed a sodium‐deficient diet

Abstract

The present study was performed to determine whether dietary sodium restriction attenuates the development of hypertension and the impairment in renal hemodynamics that occur during the induction of the Ren2 gene in Cyp1a1‐Ren2 rats. Male Cyp1a1‐ Ren2 rats (n=5–6/group) were fed either a normal salt (0.6%) or salt‐deficient diet (<0.01%) containing indole‐3‐carbinol (I3C; 0.15%, wt/wt) for 16 days to induce slowly progressive ANG II‐dependent hypertension. The rats were then anesthetized with pentobarbital sodium and surgically prepared for measurement of mean arterial pressure (MAP), renal hemodynamics and renal excretory function. There were no significant differences between the induced normal salt group and the induced salt‐deficient group regarding MAP (183±4 vs. 181±5 mmHg), RVR (33.7±2.4 vs. 31.1±3.8 mmHg/mL/min.g), RPF (2.78±0.20 vs. 2.91±0.35 mL/min.g), or GFR (0.90±0.06 vs. 0.91±0.08 mL/min.g). Both groups had similar urine flows (41.1±1.3 vs. 39.0±6.9 μL/min), urinary sodium excretions (2.9±0.5 vs. 2.4±0.9 μEq/min) and fractional sodium excretions (0.94±0.15 vs. 0.76±0.22%). These data demonstrate that a sodium‐deficient diet does not attenuate the increase in arterial blood pressure or the associated renal functional derangements in Cyp1a1‐Ren2 transgenic rats with slowly progressive ANG II‐dependent hypertension.Support: NHLBI, Tulane COBRE in Hypertension and Renal Biology.