[Renal functional reserve in obstructive nephropathy]

This study was designed to evaluate renal functional reserve (RFR) in obstructive nephropathy using amino acid loading and the effect of angiotensin converting enzyme (ACE) inhibitor on RFR. We divided 24 rabbits into 4 groups, consisting of a control, 6-hours-bilateral ureteral obstruction (BUO), 24-hour BUO and 24-hour BUO pretreated with ACE inhibitor. Following the ligation of the bilateral ureters at the vesicoureteral junction, a unilateral ureter was released after a 6-hour or 24-hour duration in the obstructive groups. We measured RFR and renal vascular resistance after releasing a unilateral ureter in BUO. The baseline GFR values in the 6-hour and 24-hour BUO groups were significantly lower than that in the control. RFR were 0.34 + 0.04 ml/min/kg (control), 0.10 + 0.03 (6-hour BUO), 0.01 + 0.03 (24-hour BUO) and 0.10 + 0.01 (ACE inhibitor), respectively. RFR in the 6-hour BUO group was well preserved compared with that in the 24-hour BUO group. Pretreatment with ACE inhibitor in the 24-hour BUO group enhanced RFR to the extent of 6-hour BUO. Our results demonstrated that angiotensin II plays an important role in decreased GFR with obstructive nephropathy. Moreover, the present data suggested that evaluation of RFR might play a key role in the recovery of the post-obstructive renal function.