title: Effect of hydrogen peroxide and catalase on rat cerebellum nitric oxide synthase.
abstract: The effect of H2O2 and catalase on isolated rat cerebellum nitric oxide (NO) synthase activity was determined by measuring the conversion of L-[3H]arginine to L-[3H]citrulline. H2O2 (1-5 mM) markedly increased NO synthase activity in the presence of endogenous catalase (72 +/- 4 U/mL). This effect of H2O2 was further increased by exogenous catalase (200 U/mL). Exogenous catalase (0.1 to 1000 U/mL) by itself had no significant effect on NO synthase activity. Nitroblue tetrazolium chloride, an electron acceptor, inhibited NO synthase activity in a concentration-dependent manner. This study suggests that H2O2 is not directly involved in NO synthesis and that the H2O2/catalase stimulation of NO synthase activity may be due to the excess oxygen produced by the H2O2/catalase system.
authors.affiliation: Department of Anesthesiology, University of Virginia Health Sciences Center, Charlottesville 22908.
authors.forename: A
authors.initials: A
authors.lastname: Rengasamy
authors.forename: R A
authors.initials: RA
authors.lastname: Johns
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000378:metabolism; D002374:Catalase / Q000494:pharmacology*; D002531:Cerebellum / Q000187:drug effects* / Q000201:enzymology; D002956:Citrulline / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase; D051381:Rats; D013778:Tetrazolium Salts / Q000494:pharmacology
chemical_list: D013778:Tetrazolium Salts; C042207:4-anisyltetrazolium blue; D002956:Citrulline; D009569:Nitric Oxide; D001120:Arginine; D006861:Hydrogen Peroxide; D002374:Catalase; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases