The effect of experimental hydronephrosis on clearance data.

Partial obstruction of one ureter was created in newborn rats and its effects were studied in the adult rat. The obstructed renal pelvis was found to be enlarged 2-3 times. The weight of the kidney on this side was 85% of the contralateral one. Inulin clearance was measured in a way, which allowed comparison between the conventional technique and a modified technique, designed to circumvent the dilution in the enlarged pelvis. With the conventional technique, filtration was 32% of that in the contralateral kidney, whereas with the new technique true filtration of the hydronephrotic kidney was 82% (p less than 0.001). The modified technique is evaluated and the implications of the functional results are discussed.