title: Effect of hyperoxia on superoxide anion and hydrogen peroxide production of polymorphonuclear leucocytes and alveolar macrophages.
abstract: Hyperoxia activates superoxide dismutase (SOD) while inactivating catalase and glutathione peroxidase in polymorphonuclear leucocytes (PMN) and alveolar marcophages (AM) obtained from guinea-pigs exposed to 85% oxygen for 90 h. The influence of these altered enzyme activities on the rate of oxygen consumption and release of superoxide anion (O--2) and hydrogen peroxide (H2O2) was investigated. By 18 h O--2 released from resting PMN increased two-fold and remained elevated through the entire periods of the study, whereas H2O2 release and oxygen consumption at the same time points remained normal. At 66 h PMN phagocytizing opsonized zymosan particles released additional quantities of O--2 and H2O2 and consumed significantly more oxygen compared to the usual increase noted at earlier time points. Although oxygen consumption was almost two-fold higher in AM than PMN, phagocytizing AM released three-fold less O--2 and five-fold less H2O2 than did PMN. Furthermore, AM of animals exposed to hyperoxia no longer exhibited enhanced O--2 production upon exposure to opsonized zymosan. Hydrogen peroxide release progressively decreased at rest but progressively increased during phagocytosis of opsonized zymosan during the 90 h exposure to hyperoxia. No changes in oxygen consumption of AM occurred during hyperoxia. The divergent oxidative responses in PMN and AM of guinea-pigs exposed to hyperoxia suggest different biochemical adaptive mechanisms.
mesh_terms: D000818:Animals; D006168:Guinea Pigs; D006861:Hydrogen Peroxide / Q000378:metabolism*; D066298:In Vitro Techniques; D008264:Macrophages / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism*; D010100:Oxygen; D010101:Oxygen Consumption; D010587:Phagocytosis; D011650:Pulmonary Alveoli / Q000166:cytology; D013481:Superoxides / Q000378:metabolism
chemical_list: D013481:Superoxides; D006861:Hydrogen Peroxide; D010100:Oxygen