Renal function after release of chronic unilateral hydronephrosis in man.

Differential renal function studies performed on ten patients after release of unilateral hydronephrosis revealed that the previously obstructed kidney exhibits abnormalities in a number of physiological indexes. Many of the obstructed kidneys had an impairment of glomerular filtration rate, concentrating ability, acidification, sodium reabsorption and tubular maximal secretion of para-aminohippurate with normal urinary dilution. Despite impairment of sodium and water reabsorption, none of these patients, nor 20 additional patients, had a significant postobstructive diuresis from the previously obstructed kidney. All of the patients had normal total renal function. Thus, the changes observed were a result of the obstructive injury and were not related to azotemia or aberrations in water or sodium metabolism.