title: Is nitric oxide (NO) an antioxidant or a prooxidant for lipid peroxidation?
abstract: Antioxidant and prooxidant effects of nitric oxide (NO) on lipid peroxidation in aqueous and non-aqueous media were examined. In an aqueous solution, NO did not induce peroxidation of unoxidized methyl linoleate (ML) and suppressed the radical initiator-induced oxidation of ML. NO suppressed the Fe(II) ion-induced oxidation of mouse liver microsomes. NO reduced the O2 consumption during the radical initiator-induced oxidation of linoleic acid in an aqueous medium. NO conversion into NO2- in an aqueous medium was not affected by unoxidized ML and was slightly reduced by peroxidizing ML. On the other hand, as well as pure NO2, NO induced peroxidation of unoxidized ML in n-hexane in a dose-dependent fashion. NO did not suppress the radical initiator-induced oxidation of ML in n-hexane. Nitrogen oxide species (NO2 or N2O3) formed by autoxidation was dramatically lost in n-hexane in the presence of unoxidized ML. The results indicated that NO terminated lipid peroxidation in an aqueous medium, whereas NO induced lipid peroxidatiton in a non-aqueous medium. Hence, NO showed both antioxidant and prooxidant effects on lipid peroxidation depending on the solvents.
authors.affiliation: School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Hiramoto
authors.forename: Takumi
authors.initials: T
authors.lastname: Ohkawa
authors.forename: Natsuki
authors.initials: N
authors.lastname: Oikawa
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Kikugawa
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry*; D006586:Hexanes; D066298:In Vitro Techniques; D007501:Iron / Q000494:pharmacology; D008041:Linoleic Acids / Q000737:chemistry; D015227:Lipid Peroxidation / Q000187:drug effects*; D051379:Mice; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D010101:Oxygen Consumption / Q000187:drug effects; D012996:Solutions; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
chemical_list: D000975:Antioxidants; D006586:Hexanes; D008041:Linoleic Acids; D016877:Oxidants; D012996:Solutions; D017392:Thiobarbituric Acid Reactive Substances; C005575:methyl linoleate; C026385:n-hexane; D009569:Nitric Oxide; D007501:Iron