title: The effects of peroxynitrite on erythrocytes.
abstract: Endotoxin-induced peroxynitrite formation has been demonstrated in plasma. The aim of this study is to evaluate whether this has an effect on erythrocytes. For this purpose erythrocyte 3-nitrotyrosine (3-NT) level, Na+-K+ ATPase and glutathione peroxidase activities were measured both in vivo and in vitro. In vivo peroxynitrite formation was induced in rats by intraperitoneal Escherichia coli (E.coli) injection. Erythrocytes were directly incubated with peroxynitrite in the in vitro experiment. 3-NT levels were measured by reverse-phase HPLC, glutathione peroxidase, and Na+-K+ ATPase activities were measured by spectrophotometric techniques. There was a marked increase in the 3-NT levels in both experiments. However, glutathione peroxidase activity was significantly increased in in vivo experiments, while decreasing in in vitro conditions. Although Na+-K+ ATPase activities were significantly reduced by peroxynitrite in vitro, Na+-K+ ATPase activities were similar in control and E.coli-injected rat erythrocytes. Although nitrating effect of peroxynitrite does not seem to be preventable by endogenous antioxidants, this effect of peroxynitrite may not endanger erythrocytes if the oxidative damage of peroxynitrite is prevented.
authors.affiliation: Faculty of Medicine, Biochemistry Department, Gazi University, Ankara, Turkey.
authors.forename: N
authors.initials: N
authors.lastname: Türközkan
authors.forename: A
authors.initials: A
authors.lastname: Unlü
authors.forename: A
authors.initials: A
authors.lastname: Ertabak
authors.forename: B
authors.initials: B
authors.lastname: Cimen
authors.forename: U
authors.initials: U
authors.lastname: Karabicak
mesh_terms: D000483:Alleles; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004790:Enzyme Induction; D004912:Erythrocytes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D004926:Escherichia coli / Q000502:physiology; D004927:Escherichia coli Infections / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D018384:Oxidative Stress; D030421:Peroxynitrous Acid / Q000378:metabolism* / Q000494:pharmacology*; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013053:Spectrophotometry; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D030421:Peroxynitrous Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; D005979:Glutathione Peroxidase; D000254:Sodium-Potassium-Exchanging ATPase