INTRARENAL HEMODYNAMICS AND URETERAL PRESSURE DURING URETERAL OBSTRUCTION

Abstract

Renal blood flow [RBF] was measured in bilateral ureteral obstruction (BUO) and unilateral ureteral (UUO) obstruction. RBF of BUO and UUO rats before release of 24 h obstruction was approximately 69% and 77% of control values, respectively. No redistribution of intrarenal blood flow was noted in UUO and BUO rats. Prerelease ureteral pressure of BUO rats (27.6 .+-. 1.60 mm Hg) was significantly higher than that of UUO rats (14.4 .+-. 1.30 mm Hg, P < 0.001). Although the blood urea nitrogen [BUN] of UUO rats with urine reinfusion was similar to that of BUO rats, the ureteral pressure was 14.8 .+-. 1.93 mm Hg. The higher ureteral pressure of BUO rats was not due to elevation of BUN. Decreased RBF during obstruction and high ureteral pressure may result in more severe tubular damage in BUO than in UUO. The decreased renal perfusion was probably due to changes in intrarenal vascular tone rather than due to interstitial pressure.