l-arginine supplementation influenced nitrite but not nitrate and total nitrite in rabbit model of hypercholesterolemia

background: the assessment of altered nitric oxide (no) availability is of potentially important diagnostic and prognostic significance. the present study is aimed to investigate the effect of l-arginine (as a natural no donor) supplementation on no metabolite in a rabbit model of hypercholesterolemia to find a reliable marker for endothelial no production. methods: white male rabbits (n = 30) randomly assigned to 2 groups. rabbits were fed 1% high-cholesterol diet (hc group, n = 15), or hc diet with oral l-arginine (3% in drinking water) (hc + l-arginine group, n = 15) for 4 weeks. the serum levels of lipids, l-arginine, total no metabolites (nox), nitrite and nitrate were measured before and after the study. results: in this study, l-arginine supplementation led to a significant increased plasma level of l-arginine. the serum level of nitrite was significantly higher in l-arginine treated group while serum level of nitrate and nox was significantly lower than hc group. conclusion: as the result of our study showed, nitrite is a useful marker of endogenous endothelial no production and although frequently used, neither nitrate nor nox are reliable markers of acute changes in endothelial no synthase activity.