[An experimental study of PAH clearance in chronic unilateral and completely obstructed kidney].

The following experiment was performed to estimate PAH clearance of chronic unilateral and completely obstructed kidney and to explore its change during obstruction period. Thirty adult male mongrel dogs were used. Unilateral complete ureteral obstruction was made by ligation of the left ureter proximal to the bladder. After 3, 5, 10, 20 and 40 days of obstruction, an experiment was performed. Under laparotomy, the left kidney was exposed and polyethylene catheter was inserted into the renal pelvis. Intrapelvic pressure was monitored by pressure transducer. In a condition that PAH (p-aminohippurate) was constantly infused intravenously, intrapelvic urine of the obstructed kidney was exchanged for physiological saline. After the exchange, intrapelvic PAH concentration was measured at hourly intervals for 4 hours. At each midpoint of the measurements, plasma PAH concentration was measured. At the end of the experiment, the obstructed kidney was resected and pelvic capacity was measured. PAH of the obstructed pelvis increased at hourly intervals after the exchange. The result showed that the clearance ability was maintained in the completely obstructed kidney. PAH clearance values were 16.3, 13.6, 1.0, 0.9, 0.9 ml/hr/kg b.w. at 3, 5, 10, 20 and 40 days obstruction respectively. PAH clearance decreased sharply during early stage of obstruction and tended to reach a fixed low value at over 10 days of obstruction. Our experimental method seemed to be available to estimate the clearance ability of chronically, unilaterally and completely obstructed kidney.