Diuretic effect of NG-nitro-l-arginine methyl ester in the rat

Abstract— Intravenous infusion of the nitric oxide synthase inhibitor N^G-nitro-l -arginine methyl ester, l -NAME (10 μg kg^?1 min^?1), to anaesthetized rats produced a diuresis and natriuresis. By contrast, infusion of the same dose of N^G-nitro-d -arginine methyl ester had no effect on either urine output or sodium excretion. The effects of l -NAME were first evident 120 min after the start of infusion and by 170 min a fivefold increase in urine volume and sodium excretion was recorded. l -NAME also produced a transient fall in inulin clearance and a persistent decline in renal blood flow. These renal effects of l -NAME were associated with a gradual elevation of mean arterial blood pressure, although this only attained statistical significance, in comparison with saline-infused animals, 170 min after the start of infusion. The findings indicate the diuresis and natriuresis evoked by l -NAME in the rat is a result of a direct tubular action together with a pressure diuresis.