Abstract
To clarify the precise relationship between sodium and nitric oxide (NO), we studied the effects of altered sodium intake on NO production. Male Wistar rats were maintained on a low-sodium (0.2% NaCl), normal-sodium (2% NaCl), or high-sodium (8% NaCl) diet for 10 days or 8 weeks; 24-h urine was collected at those times for assay of nitrate ion (NO3-), a stable metabolite of NO, and of cyclic GMP. Urinary excretion of NO3- and cyclic GMP was increased on the 10th day in the low-sodium group, as compared with the normal- and high-sodium groups. The urinary excretion of cyclic GMP was increased at the 8th week, and NO3- showed a tendency to increase in the low-sodium group, as compared with the high-sodium group. An up- regulation of NO production may explain, at least in part, the antihypertensive effect of sodium restriction. (Hypertens Res 1997; 20: 57-60)
