Glomerular dynamics in rats with hereditary hydronephrosis.

Micropuncture and metabolic studies were performed using Sprague-Dawley rats with hereditary hydronephrosis secondary to vesicoureteric reflux. Whole kidney and single nephron glomerular filtration rates in hydronephrotic and nonhydronephrotic rats were essentially identical. Filtration rates were maintained near normal in hydronephrotic rats because of an elevation in the mean glomerular transcapillary hydraulic pressure difference which effectively offsets a lower initial glomerular capillary plasma flow rate and a possible decrease in the glomerular capillary ultrafiltration coefficient relative to nonhydronephrotic rats. Additional renal abnormalities, including a urinary concentrating defect, a renal sodium conserving defect, and calcium apatite nephrolithiasis, were also found in hydronephrotic rats.