Evaluation of endothelial free radical release by vascular tension responses in insulin-resistant rat aorta

Mechanical responses to super oxide anion scavengers and nitric oxide (NO) synthase inhibitors in aortic endothelial cells were compared in normal cho w-fed rats and those made insulin-resistant by feeding of fructose. CU2+, Z n2+-superoxide dismutase-induced vascular relaxation and superoxide product ion, measured by the lucigenin-enhanced chemiluminescence method, were grea ter in aortas from fructose-fed rats than in those from normal chow-fed rat s. N-G-nitro-L-arginine-induced contractions due to suppression of NO synth ase activity were smaller in aortas from fructose-fed rats. Vascular mechan ical responses may reflect the generation of superoxide and NO by the endot helium. Thus, isometric tension studies may be a useful tool for evaluating the production of these radicals in blood vessels. (C) 2000 Elsevier Scien ce B.V. All rights reserved.