Effects of Ureteral Pressure Increase on Renal Hemodynamics and the Handling of Electrolytes and Water

Abstract

The influence of increase in ureteral pressure was studied in acute expts. in anesthetized dogs receiving isotonic or hypertonic Ringer''s infusion. The following functions were examined: Na, K a water excretion; creatinine and inulin clearance, for measurement of GFR; PAH clearance to measure effective plasma flow; and TmG and TmPAH. Reduction in these functions during 52 cm. of ureteral pressure increase was observed of the following approx. magnitude considered as percentage of the simultaneous control kidney: Na and water, 55 %; K, 80%; GFR, 85%; plasma flow, 95%; TmG and TmPAH showed no significant changes. Effects were less during an initial elevation of 36 cm. of water. The decrease in electrolyte and water excretion is believed to be caused by reduction in filtration rate resulting in reduction of load to the tubular cells with more complete reabsorption. Expts. confirming this interpretation showed that when filtration rate was restored by an increase in renal arterial pressure during ureteral pressure elevation, excretion of Na, K and water tended to be restored.