ROLE OF ENDOTHELIUM-DERIVED NITRIC-OXIDE ENDOTHELIN BALANCE IN CONTRAST MEDIUM-INDUCED ACUTE RENAL VASOCONSTRICTION IN DOGS

Rationale and Objectives. The authors evaluated the involvement of nit ric oxide and endothelin in radiographic contrast medium-induced chang es in renal hemodynamics. Methods. Eleven anesthetized healthy dogs we re each studied during three periods. Thirty minutes before the first, second, and third periods, the dogs received I mt per kilogram of bod y weight of isotonic saline, L-N-nitro-L-arginine-methyl-ester (L-Name , 10 mg/kg intravenously), and L-arginine (500 mg/kg intravenously), r espectively. Renal blood how (RBF) and mean arterial blood pressure we re continuously monitored. The glomerular filtration rate (GFR) was ev aluated by means of polyfructosan clearance. Results. Contrast medium induced a significant (P < .05) decrease in RBF and GFR and a signific ant (P < .05) increase in urinary endothelin excretion, L-Name enhance d the effect of contrast media on RBF and GFR. L-arginine attenuated t he effect of L-Name on the contrast medium-induced reduction of GFR. C onclusion. These findings support the hypothesis that acute contrast m edium-induced intrarenal vasoconstriction map involve an imbalance of endothelial vasoactive agents, nitric oxide, and endothelin, and they confirm the involvement of hemodynamic changes in contrast medium-indu ced nephropathy.