Tanaka S, Yashiro A, Nakashima Y, Nanri H, Ikeda M, Kuroiwa A
Second Department of Internal Medicine, University of Occupational and Environmental Health, Japan, School of Medicine, Kitakyushu.
Clin Cardiol. 1997 Apr;20(4):361-5. doi: 10.1002/clc.4960200412.
Plasma nitrite/nitrate (NOx) is a stable end product of the vasodilator nitric oxide (NO). However, there are few reports about plasma NOx levels in humans.
The purpose of this study was to assess the availability of plasma NOx for evaluating basal endogenously-synthesized or endothelium-derived NO, and to examine whether NOx levels are lowered in patients with coronary artery disease (CAD) or its risk factors.
Plasma NOx levels were measured using an automated system based on the Griess reaction. NOx levels for a 24-h period reproducibly became lowest at 6 A.M. in restricted healthy volunteers, and became stable in inpatient volunteers at 6 A.M. within 4 days after admission.
Based on these findings, NOx levels at 6 A.M. in inpatients can be considered as the basal levels. In 40 inpatients suspected of CAD (28 men, 12 women; mean age 60 +/- 11 years), the basal levels of NOx were not related to CAD and its risk factors, except for hypercholesterolemia. The NOx level of patients with hypercholesterolemia was significantly lower than that of patients with normal cholesterol (n = 16,34 +/- 16 mumol/l vs. n = 24, 49 +/- 23 mumol/l, p < 0.03). Furthermore, the NOx levels correlated negatively with the total cholesterol and low-density lipoprotein cholesterol levels (r = -0.40, p < 0.01; r = -0.47, p < 0.003, respectively), but not with other lipid fraction levels.
The results suggest that the quantity of basal endothelium-derived NO synthesis may be decreased in the presence of hypercholesterolemia.
血浆亚硝酸盐/硝酸盐（NOx）是血管舒张剂一氧化氮（NO）的稳定终产物。然而，关于人类血浆NOx水平的报道较少。
本研究的目的是评估血浆NOx用于评估内源性基础合成或内皮源性NO的可用性，并检查冠状动脉疾病（CAD）患者或其危险因素患者的NOx水平是否降低。
使用基于格里斯反应的自动化系统测量血浆NOx水平。在受限的健康志愿者中，24小时期间的NOx水平在上午6点可重复性地降至最低，住院志愿者在入院后4天内上午6点时趋于稳定。
基于这些发现，住院患者上午6点的NOx水平可被视为基础水平。在40名疑似CAD的住院患者中（28名男性，12名女性；平均年龄60±11岁），除高胆固醇血症外，NOx的基础水平与CAD及其危险因素无关。高胆固醇血症患者的NOx水平显著低于胆固醇正常的患者（n = 16，34±16μmol/L对n = 24，49±23μmol/L，p < 0.03）。此外，NOx水平与总胆固醇和低密度脂蛋白胆固醇水平呈负相关（r = -0.40，p < 0.01；r = -0.47，p < 0.003），但与其他脂质组分水平无关。
结果表明高胆固醇血症存在时基础内皮源性NO合成量可能减少。
