EFFECT OF CHRONIC N-G-NITRO-L-ARGININE METHYL-ESTER (L-NAME) ON BLOOD-PRESSURE AND RENAL-FUNCTION IN CONSCIOUS UNINEPHRECTOMIZED SPONTANEOUSLY HYPERTENSIVE RATS

We have studied during 30 days the effect of a low dose of N-G-nitro-L -arginine methyl ester (1 mg.kg(-1).day(-1) in drinking water) in the presence of D-or L-arginine (1 mg.kg(-1).day(-1) in drinking water) in comparison with D- or L-arginine alone on blood pressure and renal fu nction in conscious uninephrectomized female spontaneously hypertensiv e rats. At the end of the study, there was a significant increase in s ystolic blood pressure in the N-G-nitro-L-arginine methyl ester + D-ar ginine group (307 +/- 6 mmHg (1 mmHg = 133.3 Pa), n = 14,p < 0.05) in comparison with N-G-nitro-L-arginine methyl ester + L-arginine (281 +/ - 6 mmHg, n = 14), L-arginine (262 +/- 5 mmHg, n = 13), and D-arginine (258 +/- 7 mmHg, n = 12) groups. There were no changes in diuresis, p roteinuria, or sodium and potassium excretion between differently trea ted animals during this study. These results suggest that in uninephre ctomized female spontaneously hypertensive rats, after 1 month blockad e of NO synthesis with a low dose of N-G-nitro-L-arginine methyl ester , vasculature is under tonic control by NO and it is not correlated wi th renal dysfunction.