Catalase-dependent peroxidative metabolism in the alveolar macrophage during phagocytosis

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Abstract
Evidence for the presence of peroxidative metabolism in rabbit alveolar macrophages (AM) has been obtained from the following observations: (a) catalase is present in high concentrations; (b) peroxidase activity could not be detected employing guaiacol as substrate; (c) the irreversible inhibition of AM catalase by aminotriazole served as a detection system for H2O2 and demonstrated increased intracellular H2O2 after phagocytosis; (d) formate oxidation, a marker of catalase-dependent peroxidations, occurs in resting AM and is increased by phagocytosis; (c) measurements of H2O2 accumulation in a dialysate of AM demonstrated twofold increase during phagocytosis; and (f) aminotriazole diminishes O2 utilization and 14CO2 production from labelled glucose and pyruvate. It is concluded that, while catalase-dependent H2O2 metabolism is not essential for particle entry, this pathway represents one of the metabolic pathways stimulated by particle entry in the AM.