title: Direct evidence for in vivo hydroxyl-radical generation in experimental iron overload: an ESR spin-trapping investigation.
abstract: Although the hydroxyl radical is often implicated as the species responsible for the initiation of oxidative damage in iron-overload conditions, no ESR evidence for the formation of the radical in vivo has been reported. We have employed a secondary radical-trapping technique in which the hydroxyl radical reacts with dimethyl sulfoxide to form the methyl radical, which is then detected as its adduct of the spin trap N-t-butyl-alpha-phenylnitrone in the bile of animals given an intragastric dose of ferrous sulfate. The identity of this adduct was verified by isotope-substitution techniques. We show that unless measures are taken to inactivate the iron excreted in the bile of treated animals, reactions between iron, oxygen, dimethyl sulfoxide, N-t-butyl-alpha-phenylnitrone, and bile components lead to the formation of artifacts during sample collection.
authors.affiliation: Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709.
authors.forename: M J
authors.initials: MJ
authors.lastname: Burkitt
authors.forename: R P
authors.initials: RP
authors.lastname: Mason
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry; D000818:Animals; D001646:Bile / Q000378:metabolism; D003497:Cyclic N-Oxides; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D006878:Hydroxides / Q000737:chemistry*; D007501:Iron / Q000737:chemistry / Q000633:toxicity*; D008297:Male; D009589:Nitrogen Oxides / Q000737:chemistry; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains; D013113:Spin Labels
chemical_list: D003497:Cyclic N-Oxides; D005609:Free Radicals; D006878:Hydroxides; D009589:Nitrogen Oxides; D013113:Spin Labels; C029217:phenyl-N-tert-butylnitrone; D015082:2,2'-Dipyridyl; D007501:Iron; D004121:Dimethyl Sulfoxide