title: Activation and increment of alveolar macrophages induced by nitrogen dioxide.
abstract: Male Wistar rats were exposed to 4 ppm nitrogen dioxide (NO2) for 10 d, and at intervals alveolar macrophages were collected by pulmonary lavage. A metabolic enhancement of alveolar macrophages was observed on d 4 of exposure. The specific activities of glucose-6-phosphate dehydrogenase and glutathione peroxidase of the peroxidative metabolic pathway increased to 1.29-fold (p less than 0.001) and 1.17-fold (p less than 0.05) those of the control values, respectively. The specific activities of succinate-cytochrome c reductase of the mitochondrial respiratory system and pyruvate kinase of the glycolytic pathway also increased to 1.17-fold (p less than 0.01) and 1.20-fold (p less than 0.01) those of the control values, respectively. In addition, the incorporation of [3H]leucine and [14C]thymidine into alveolar macrophages were elevated to 1.77-fold (p less than 0.001) and 1.84-fold (p less than 0.01) those of the control values, respectively. The activities of all enzymes tested decreased to control levels by d 10. The number of alveolar macrophages collected from exposed animals increased to 1.24-fold (p less than 0.01) that of the control value on d 7 and was maintained at a significantly higher level until d 10. Alveolar macrophages were heterogeneous in size (7-21 micron in diameter), and most of them were distributed between 11 and 17 micron in diameter. Exposures to 4 ppm NO2 increased significantly the cells of 9-13 micron in diameter on the seventh day. These results show that exposures to 4 ppm NO2 cause a metabolic enhancement and subsequent increase in alveolar macrophages.
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009585:Nitrogen Dioxide / Q000494:pharmacology*; D014176:Protein Biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
chemical_list: D009585:Nitrogen Dioxide