ROLE OF NITRIC-OXIDE (EDRF) IN RADIOCONTRAST ACUTE-RENAL-FAILURE IN RATS

This study was undertaken to examine the possible role of endothelium- derived relaxing factor (EDRF), identified as nitric oxide (NO), in th e pathogenesis of radiocontrast-induced acute renal failure in rats. N ormal and salt-depleted rats were monitored for 60 min or 24 h after r adiocontrast administration. The administration of L-arginine to norma l rats abolished the immediate decrease in p-aminohippurate clearance (C-PAH) and attenuated the decrease in inulin clearance (C-In). The ad ministration of NO synthase inhibitor to the salt-depleted animals res ulted in a significantly more pronounced decrease in C-PAH compared wi th both the control and the L-arginine-treated animals. The recovery o f C-In 24 h after radiocontrast administration to the salt-depleted ra ts was significantly better in the L-arginine-treated rats than in eit her the control or inhibitor-treated groups. The administration of rad iocontrast material resulted in a significant decrease in urinary guan osine 3',5'-cyclic monophosphate as well as NO2 + NO3 excretion. This decrease was significantly attenuated by L-arginine. Our results 1) su ggest that NO plays a major role in the pathogenesis of radiocontrast- induced acute renal failure and 2) suggest a novel therapeutic approac h, i.e., the use of L-arginine in this form of acute renal failure.