The reduction of glutathione disulfide produced by t-butyl hydroperoxide in respiring mitochondria.
Factors affecting the reduction of GSSG by rat liver mitochondria after a t-butyl hydroperoxide-induced (t-BOOH) oxidative stress were studied. The amounts of ADP and mitochondrial protein were adjusted to consume less than 50% of the available oxygen during the 8-min experimental period. A 4-min treatment of mitochondria with 24 nmol t-BOOH/mg protein (60 microM) oxidized 91% of total glutathione. In the presence of glutamate/malate, succinate or ascorbate/N,N,N',N'-tetramethyl-p- phenylenediamine (TMPD) (state 4 respiration), 84, 84, and 28% of the GSSG formed during t-BOOH treatment was reduced after 4 min, respectively. A similar extent of reduction was seen during state 3 respiration (1.5 mM ADP) with glutamate/malate, but no reduction occurred during state 3 respiration with either succinate or ascorbate/TMPD. The succinate-supported reduction of GSSG was completely blocked by rotenone, antimycin A, carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), or 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). In contrast, oligomycin potentiated GSSG reduction using either glutamate/malate or succinate as substrates. Rotenone partially blocked glutamate/malate-supported GSSG reduction. NADPH levels were altered in direct proportion to the effects on GSSG reduction. The current data indicate that the reduction of GSSG in oxidatively-stressed isolated rat liver mitochondria occurs most efficiently during state 4 respiration and is independent of ATP synthesis. Both transhydrogenation and the transmembrane proton gradient appear to be important in NADPH regeneration and consequent GSSG reduction.
Liu
H
H
Division of Pharmacology and Toxicology, University of Texas at Austin, USA.
Kehrer
J P
JP
D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D001205:Ascorbic Acid / Q000378:metabolism; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002330:Carmustine / Q000494:pharmacology; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism; D019803:Glutathione Disulfide; D007700:Kinetics; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D009840:Oligomycins / Q000494:pharmacology; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010545:Peroxides / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000494:pharmacology; D012402:Rotenone / Q000494:pharmacology; D013386:Succinates / Q000378:metabolism; D013997:Time Factors; D014475:Uncoupling Agents / Q000494:pharmacology*; D020122:tert-Butylhydroperoxide
D009840:Oligomycins; D010545:Peroxides; D017382:Reactive Oxygen Species; D013386:Succinates; D014475:Uncoupling Agents; D012402:Rotenone; D009243:NAD; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D009249:NADP; D000968:Antimycin A; D020122:tert-Butylhydroperoxide; D005978:Glutathione; D001205:Ascorbic Acid; D002330:Carmustine; D019803:Glutathione Disulfide