Effects of Complete Ureteral Obstruction in Dogs on Kidney Function

Abstract

Effects of complete ureteral obstruction for 7, 14, 21 and 28 days on renal function, and the degree and rate of recovery following release of the obstruction were studied by renal clearance methods in dogs. On the day of release of the ureter the rate of flow from the previously obstructed kidney was sufficient to measure accurately clearances only in dogs with ureteral obstruction of 1 and 2 weeks. One hour after release, the GFR and ERPF in the dogs obstructed 2 weeks were significantly less than in those obstructed for 1 week. Subsequently, renal clearance tests were made at intervals of 1 week until maximum recovery was observed. The dogs obstructed for 1 week showed the greatest improvements in GFR and ERPF and the dog obstructed for 4 weeks showed the least improvement. The control (left) kidney was removed from five dogs 2 days after release of the right ureter. The removal of the control kidney resulted in a more prompt and greater increase of GFR and ERPF and a prompt increase in the rate of urine formation by the previously obstructed kidney in all groups. Removal of the contralateral kidney in the three dogs obstructed 2, 3 and 4 weeks caused an elevation of the NPN which never returned to normal. The ability of the previously obstructed kidney in all the groups to concentrate urine was impaired. Ability to dilute urine or to produce an alkaline and acid urine was not impaired. In three dogs the contralateral kidney was removed a number of days after maximum recovery was noted. In each case renal clearances increased, demonstrating that even after long periods of stabilization (approximately 2 years in one dog) these kidneys could still be stimulated to increase the GFR and ERPF.