title: Ethylene glycol generates free radical metabolites in rats: an ESR in vivo spin trapping investigation.
abstract: Ethylene glycol, best known as antifreeze, is most often ingested accidentally or as a substitute for alcochol by chronic alcohol abusers. The toxicity of ethylene glycol poisoning is due to its toxic metabolites rather than to ethylene glycol itself. In this study, electron spin resonance (ESR) spectroscopy has been used to study free radical generation in rats by acute ethylene glycol poisoning. The radical spin trapping technique was applied where the spin trapping agent alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) reacted with free radical metabolites to form radical adducts in vivo. The radical adducts from ethylene glycol intoxication were detected in both the bile and urine samples of male Sprague-Dawley rats. The identification of the POBN-(.)[(13)C]ethylene glycol radical adduct provides for the first time direct ESR evidence for the generation of the ethylene glycol-derived radicals during acute intoxication by ethylene glycol, suggesting a new metabolic pathway. Simultaneous administration of alcohol dehydrogenase inhibitor 4-methylpyrazole with ethylene glycol resulted in an enhanced free radical generation in the bile. This report is the first evidence of ethylene glycol free radical metabolism in rats with acute ethylene glycol intoxication.
authors.affiliation: Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA. Kadiiska@niehs.nih.gov
authors.forename: M B
authors.initials: MB
authors.lastname: Kadiiska
authors.forename: R P
authors.initials: RP
authors.lastname: Mason
mesh_terms: D000818:Animals; D001646:Bile / Q000737:chemistry / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D003676:Deferoxamine / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D019855:Ethylene Glycol / Q000378:metabolism* / Q000633:toxicity / Q000652:urine; D005609:Free Radicals / Q000032:analysis / Q000378:metabolism / Q000633:toxicity / Q000652:urine; D050356:Lipid Metabolism; D008297:Male; D009589:Nitrogen Oxides; D011725:Pyridines; D051381:Rats; D017207:Rats, Sprague-Dawley; D013113:Spin Labels; D019097:Spin Trapping
chemical_list: D002614:Chelating Agents; D005609:Free Radicals; D009589:Nitrogen Oxides; D011725:Pyridines; D013113:Spin Labels; C043438:alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone; D019855:Ethylene Glycol; D003676:Deferoxamine