Effects of t-butyl hydroperoxide on NADPH, glutathione, and the respiratory burst of rat alveolar macrophages.
The effects of t-butyl hydroperoxide on glutathione and NADPH and the respiratory burst (an NADPH-dependent function) in rat alveolar macrophages was investigated. Alveolar macrophages were exposed for 15 min to t-butyl hydroperoxide in the presence or absence of added glucose. Cells were then assayed for concanavalin A-stimulated O2 production or for NADPH, NADP, reduced glutathione, glutathione disulfide, glutathione released into the medium and glutathione mixed disulfides. Exposure of rat alveolar macrophages to 1 X 10(-5) M t-butyl hydroperoxide causes a loss of concanavalin A-stimulated superoxide production (the respiratory burst) that can be prevented or reversed by added glucose. Cells incubated without glucose had a higher oxidation state of the NADPH/NADP couple than cells incubated with glucose. With t-butyl hydroperoxide, NADP rose to almost 100% of the NADP + NADPH pool; however, addition of glucose prevented this alteration of the NADPH oxidation state. Cells exposed to 1 X 10(-5) M t-butyl hydroperoxide in the absence of glucose showed a significant increase in the percentage GSSG in the GSH + GSSG pool and increased glutathione mixed disulfides. These changes in glutathione distribution could also be prevented or reversed by glucose. With 1 X 10(-4) M t-butyl hydroperoxide, changes in glutathione oxidation were not prevented by glucose and cells were irreversibly damaged. We conclude that drastic alteration of the NADPH/NADP ratio does not itself reflect toxicity and that significant alteration of glutathione distribution can also be tolerated; however, when oxidative stress exceeds the ability of glucose to prevent alterations in oxidation state, irreversible damage to cell function and structure may occur.
D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism*; D066298:In Vitro Techniques; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009249:NADP / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*; D010545:Peroxides / Q000494:pharmacology*; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D013481:Superoxides / Q000378:metabolism; D020122:tert-Butylhydroperoxide
D010545:Peroxides; D013481:Superoxides; D009249:NADP; D020122:tert-Butylhydroperoxide; D005978:Glutathione; D005947:Glucose