title: Cytochrome P450 destruction by benzene metabolites 1,4-benzoquinone and 1,4-hydroquinone and the formation of hydroxyl radicals in minipig liver microsomes.
abstract: Reactive metabolites of benzene 1,4-benzoquinone and 1,4-hydroquinone exert their toxic effects through covalent and/or oxidative damage to DNA and proteins. Since minipigs have been proposed as a suitable model species in toxicological and pharmacological research, the aim of this study was to explore mechanisms by which catechol, 1,4-hydroquinone and 1,4-benzoquinone destroy cytochrome P450 (P450) and induce oxidative stress in minipig liver microsomes. Our second goal was to assess the usefulness of minipig liver microsomes as a model system for the testing of the production of oxidative stress by clinically relevant quinone-containing compounds, e.g. anthracyclines. Of the three benzene metabolites tested, the highest P450 destruction was caused by 1,4-benzoquinone. This destructive effect did not correlate with the production of hydroxyl radicals as measured by ESR spin trapping which was the highest in samples containing 1,4-hydroquinone. Our results confirm previous findings that 1,4-benzoquinone exerts its effect mainly by direct attack on macromolecules while 1,4-hydroquinone rather stimulates the production of reactive oxygen species. Doxorubicin stimulated the production of hydroxyl radicals and the destruction of P450 similarly as 1,4-hydroquinone. Minipig liver microsomes should be further tested as a possibly suitable model system for the testing of potential modulators of the toxicity of doxorubicin.
authors.affiliation: 3(rd) Faculty of Medicine, Charles University, Ruská 87, 10000 Praha 10, Czech Republic. ekondrova@szu.cz
authors.forename: Eliska
authors.initials: E
authors.lastname: Kondrová
authors.forename: Pavel
authors.initials: P
authors.lastname: Stopka
authors.forename: Pavel
authors.initials: P
authors.lastname: Soucek
mesh_terms: D000465:Algorithms; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000633:toxicity; D001554:Benzene / Q000378:metabolism*; D016227:Benzoquinones / Q000378:metabolism / Q000633:toxicity*; D002396:Catechols / Q000633:toxicity; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors; D004317:Doxorubicin / Q000633:toxicity; D004578:Electron Spin Resonance Spectroscopy; D004591:Electrophoresis, Polyacrylamide Gel; D006873:Hydroquinones / Q000378:metabolism / Q000633:toxicity*; D017665:Hydroxyl Radical / Q000378:metabolism*; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D009249:NADP / Q000633:toxicity; D009919:Orchiectomy; D018384:Oxidative Stress / Q000187:drug effects; D013329:Structure-Activity Relationship; D013552:Swine; D013556:Swine, Miniature / Q000378:metabolism*
chemical_list: D000964:Antimetabolites, Antineoplastic; D016227:Benzoquinones; D002396:Catechols; D065607:Cytochrome P-450 Enzyme Inhibitors; D006873:Hydroquinones; D017665:Hydroxyl Radical; C004532:quinone; D009249:NADP; D004317:Doxorubicin; D019392:Cytochrome P-450 CYP2E1; D051544:Cytochrome P-450 CYP3A; D001554:Benzene; C031927:hydroquinone