Metabolic reduction of chromium by alveolar macrophages and its relationships to cigarette smoke.
AUTOR(ES)
Petrilli, F L
RESUMO
Pulmonary alveolar macrophages (PAM), obtained by bronchoalveolar lavage from 47 individuals, reduced hexavalent chromium [Cr(VI)] and decreased its mutagenicity. Their specific activity--mostly mediated by cytosolic, enzyme-catalyzed mechanisms--was significantly higher than in corresponding preparations of mixed-cell populations from human peripheral lung parenchyma or bronchial tree, or from rat lung or liver. At equivalent number of PAM, Cr(VI) reduction, total protein, and some oxidoreductase activities were significantly increased in smokers. No appreciable variation could be detected between lung cancer and noncancer patients. In rats, the Cr(VI)-reducing activity of PAM preparations was induced by Aroclor 1254. Thus, alveolar macrophages provide crucial defense mechanisms not only by phagocytizing metals, but also by metabolically reducing Cr(VI). The epithelial-lining fluid (ELF) also displayed some Cr(VI) reduction. Together with already investigated metabolic processes occurring inside lung cells, these mechanisms are expected to determine thresholds in the pulmonary carcinogenicity of chromium.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=370552Documentos Relacionados
- Functional and metabolic properties of alveolar macrophages in response to the gas phase of tobacco smoke.
- Immediate response to cigarette smoke.
- Variation in individual responses to the cytotoxicity of cigarette smoke.
- Relation of urinary cotinine concentrations to cigarette smoking and to exposure to other people's smoke.
- Relation of urinary cotinine concentrations to cigarette smoking and to exposure to other people's smoke.