Insulin-induced peroxynitrite production in human platelet-rich plasma

• Published in: Redox report : communications in free radical research Vol. 6; no. 4; p. 251
• Main Authors: Wittmann, I, Köszegi, T, Wagner, L, Wagner, Z, Mazák, Nagy, J
• Format: Journal Article
• Language: English
• Published: England 01-01-2001
• Subjects: Area Under Curve; Blood Platelets - drug effects; Blood Platelets - metabolism; Free Radicals; Humans; Insulin - pharmacology; Luminescent Measurements; Nitric Oxide - metabolism; Nitric Oxide Synthase - physiology; Nitric Oxide Synthase Type III; Peroxynitrous Acid - biosynthesis; Superoxides - metabolism
• ISSN: 1351-0002
• DOI: 10.1179/135100001101536409

Recent data support the possible role of nitric oxide (NO*) in the development of insulin signalling. The aim of this study was to examine the effect of insulin on NO* production by platelets. The chemiluminescence of platelet-rich plasma prepared from the blood of healthy volunteers was measured in the presence of luminol. Indirect detection of NO* by luminol is possible in the form of peroxynitrite produced in the reaction of NO* with a superoxide free radical. Luminol oxidation induced by hydroxyl free radical and lipid peroxidation was prevented by 150 micromol/l of desferrioxamine mesylate. Insulin, in the range of 0.084-840 nmol/l, induced a concentration-dependent increase in chemiluminescence, which was inhibited both by the competitive antagonist of the NO* synthase enzyme. N(omega)-nitro-L-arginine methyl ester (at concentrations of 2.0-4.0 mmol/l, P<0.001), and by the elimination of superoxide free radicals using superoxide dismutase (72-144 IU/ml, P<0.001). In conclusion, we assume that the insulin-induced increase in chemiluminescence of platelet-rich plasma was due to increased production of NO* and superoxide free radicals forming peroxynitrite. The data are consistent with production of peroxynitrite from human platelets under insulin stimulation.