title: Hydrogen peroxide in human urine: implications for antioxidant defense and redox regulation.
abstract: The presence of hydrogen peroxide, at levels sometimes exceeding 100 microM, in human urine samples was established by three different assay methods: 2-oxoglutarate decarboxylation and the ferrous oxidation-xylenol orange (FOX) assay and an oxygen electrode. Detected levels of H(2)O(2) were decreased by addition of superoxide dismutase. We conclude that urine contains autooxidizable molecules that, upon exposure to 21% O(2), undergo rapid superoxide-dependent autooxidation reactions to generate H(2)O(2). The exposure of human tissues to hydrogen peroxide may be greater than is commonly supposed, which has implications in relation to the proposed role of this species in cell signaling.
authors.affiliation: Faculty of Medicine, National University of Singapore, 10 Kent Ridge Crescent, 119260, Singapore.
authors.forename: L H
authors.initials: LH
authors.lastname: Long
authors.forename: P J
authors.initials: PJ
authors.lastname: Evans
authors.forename: B
authors.initials: B
authors.lastname: Halliwell
mesh_terms: D000328:Adult; D002250:Carbon Radioisotopes; D004563:Electrochemistry / Q000379:methods; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D006861:Hydrogen Peroxide / Q000652:urine*; D007202:Indicators and Reagents; D007656:Ketoglutaric Acids; D008297:Male; D008875:Middle Aged; D010636:Phenols; D012016:Reference Values; D012588:Scintillation Counting / Q000379:methods; D012680:Sensitivity and Specificity; D013454:Sulfoxides; D013482:Superoxide Dismutase; D014992:Xylenes
chemical_list: D002250:Carbon Radioisotopes; D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D007656:Ketoglutaric Acids; D010636:Phenols; D013454:Sulfoxides; D014992:Xylenes; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; C016833:xylenol orange