NOS3 and endothelial dysfunction: Naringin reduced blood glucose, total cholesterol, triglycerides, and low-density lipoproteins in fructose-fed rats. Naringin restored acetylcholine-mediated vasorelaxation, suggesting its potential influence on fructose-induced metabolic alterations and endothelial dysfunction. Naringin improved serum nitrate/nitrite (NOx), endothelial nitric oxide synthase (eNOS), and phosphorylated eNOS (p-eNOS) protein expression, and preserved endothelium-dependent relaxation in the aortae of the fructose-fed rats.