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Studies on biochemical effects of nitrogen dioxide. II. Changes of the protective systems in rat lungs and of lipid peroxidation by acute exposure

Journal Article · · J. Toxicol. Environ. Health; (United States)
This work was done to clarify the relation between the change of lipid peroxidation and the protective systems in lungs after NO/sub 2/ exposure. JCL:Wistar 8-wk-old male rats were exposed continuously to 10 ppm NO/sub 2/ for 2 wk. Lipid peroxidation, measured by ethane exhalation in the breath of the rats and by the reaction of thiobarbituric acid with lung homogenates, increased to a maximum at 3 d after a decline at 1 d, and then returned to the initial level (of d 0). Activities of glutathione peroxidase (GPx), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), disulfide reductase (DSR), and superoxide dismutase (SOD) in the 105,000 x g supernatant of lung homogenates were depressed slightly at 1 d. Thereafter, they increased significantly to their maximum levels from 5 to 10 d, and these maximum levels were maintained until d 14. The pattern of change of these protective enzymes was symmetric to that of lipid peroxidation after 3 d. The order of the ratio of the increased value to the initial value was G6PD > DSR > 6PGD > GR > GPx > SOD. The time course of nonprotein sulfydryls was similar to that of the protective enzymes. In contrast, the amounts of vitamin E increased to a maximum at 2 d and then returned to the initial level. The periodic change of vitamin E was similar to that of lipid peroxidation rather than that of the protective enzymes. These results suggest that the ability of the enzyme systems in lungs to protect against NO/sub 2/ fluctuated in a complex manner and the activities of the protective enzymes varied inversely with lipid peroxidation.
Research Organization:
National Inst. for Environmental Studies, Tsukuba-Ibaraki, Japan
OSTI ID:
5095622
Journal Information:
J. Toxicol. Environ. Health; (United States), Journal Name: J. Toxicol. Environ. Health; (United States) Vol. 9:1; ISSN JTEHD
Country of Publication:
United States
Language:
English