REDUCED PLASMA-CONCENTRATIONS OF NITROGEN-OXIDE IN INDIVIDUALS WITH ESSENTIAL-HYPERTENSION

Patients with essential hypertension exhibit blunted endothelium-depen dent vasodilator responses, which may be largely attributable to reduc ed bioactivity of nitric oxide (NO). Therefore, we measured the end pr oduct of NO, nitrate plus nitrite (nitrogen oxide), and examined the r elationship between the degree of hypertension and plasma nitrate plus nitrite levels in patients with essential hypertension. The combined plasma concentration of nitrate plus nitrite, end products of NO metab olism, was reduced in individuals with essential hypertension relative to that in control subjects (15.7+/-3.1 versus 22.8 +/- 1.4 mmol.L-1, P<.001); individuals with borderline hypertension showed values that were intermediate between those of the other two groups (18.2+/-1.2 mm ol.L-1, P<.001). The plasma nitrogen oxide concentration showed signif icant inverse correlations with both systolic and diastolic blood pres sures. The basal concentration of nitrogen oxide in the plasma was red uced, at least in the peripheral circulation, in individuals with esse ntial hypertension.