Plasma Nitrate/Nitrite Concentration in Healthy Population and Patients with Diabetes Mellitus - Relationships with Gender, Aging and Diabetic Complications -

Although there are numerous papers concerning nitrite/nitrate (NOx), most of them are indirect evaluations with acetylcholine or arginine analogue. Measuring the plasma concentration of NOx ([NOx]) may be a useful predictor of the vascular endothelial function. We analyzed [NOx] in healthy mass population and investigated the relationship with gender, aging and some diabetic complications. The subjects were 738 healthy volunteers (512 males and 226 females), who received annual medical check and were considered healthy based on physical and laboratory find- ings, and 289 patients with type 2 diabetes mellitus attending our hospital, a total of 1,027 subjects. [NOx] was measured by chemiluminescense assay (Sivers Inc. Model 280). The results at the fast- ing stage were as follows: the mean value of [NOx] in the healthy subjects was 47.5±26 (μM/L), and the ratio of nitrite to nitrate was approximately 1:6. After an intake of celery containing rich nitric compounds, [NOx] markedly increased to 2.5 times, mainly because of an increase in nitrate. In the male subjects, [NOx] gradually increased with aging, whereas in the females, it tended to decrease until the menopausal stage but turned upward after that. [NOx] in the group without any diabetic complication was much lower than that in the control group (P < 0.01), but the group with coronary artery disease showed a higher value (P < 0.001). In conclusion, [NOx] was influenced by exogenous factors, aging, and difference of gender, and showed some correlations with hyper- glycemic vascular impairments.