Diphenyleneiodonium, an NAD(P)H oxidase inhibitor, also potently inhibits mitochondrial reactive oxygen species production.
Diphenyleneiodonium (DPI) has frequently been used to inhibit reactive oxygen species (ROS) production mediated by flavoenzymes, particularly NAD(P)H oxidase. This study was undertaken to examine if DPI could also inhibit production of superoxide and H2O2 by mitochondria, the major source of cellular ROS. Detection of mitochondrial superoxide by lucigenin-derived chemiluminescence (CL) with unstimulated monocytes/macrophages showed that DPI at concentrations that inhibit NAD(P)H oxidase markedly diminished the production of superoxide by mitochondrial respiration. Similarly, the extracellular H2O2 derived from mitochondrial respiration as detected by luminol-derived CL in the presence of horseradish peroxidase was also greatly reduced by DPI. DPI was as potent as rotenone in inhibiting the production of superoxide and H2O2 by mitochondrial respiration. With substrate-supported isolated mitochondria, DPI was shown to reduce mitochondrial superoxide production probably through inhibiting NADH-ubiquinone oxidoreductase (complex I).
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Department of Environmental Health Sciences, Johns Hopkins University School of Hygiene and Public Health, Baltimore, Maryland, 21205, USA.
Trush
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D000166:Acridines / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors / Q000378:metabolism; D008163:Luminescent Measurements; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism*; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009861:Onium Compounds / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013481:Superoxides / Q000037:antagonists & inhibitors / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000166:Acridines; D004791:Enzyme Inhibitors; D009861:Onium Compounds; D017382:Reactive Oxygen Species; D013481:Superoxides; C033472:10,10'-dimethyl-9,9'-biacridinium; C007517:diphenyleneiodonium; D006861:Hydrogen Peroxide; D019255:NADPH Oxidases; D013755:Tetradecanoylphorbol Acetate