Chloride Retention in Hydronephrosis

In a previous paper (Keith and Pulford) we described a method for producing experimental hydronephrosis, which permitted the study of renal function in this condition for periods varying from weeks to months. The method used was the partial obstruction of both ureters near the ureteropelvic juncture. After a thorough functional study of hydronephrosis thus produced, further experiments were carried out to ascertain how quickly normal function could be restored after ureteral obstruction was removed. It was found that if the obstruction was removed within a week, renal function was rapidly reestablished, but ureteral obstruction of longer duration often led to permanent damage to the kidney. This method of production of a lesion in the kidney with the later withdrawal of the original cause offered unusual opportunities for observing the excretory function of the kidney during the acute and later reparative stage of a pathologic process. In our previous work the excretion of nitrogenous bodies, particularly urea, andphenolsulfonephthalein was emphasized, whereas at present we are reporting observations on the excretion of chlorides. We have noted in hydronephrosis that the regulating mechanism concerned in excretion of chloride differs in several respects from that controlling the elimination of urea and phenolsulfonephthalein. This finding is in agreement with the results obtained by Widal and Javal, and McLean in other types of renal lesions. In the present study it will be shown that the water and chloride. intake must be carefully controlled. Further, it was found that when both urea and chlorides are retained they do not accumulate quantitatively in the same degree in the blood plasma.