Cytochrome c oxidase activity in tissues of rats exposed to polyurethane pyrolysis fumes
Thomas, W.C.; O'Flaherty, E.J.
Toxicology and Applied Pharmacology 49(3): 463-472
1979
ISSN/ISBN: 0041-008X PMID: 224530 Document Number: 142990
Adult male rats were exposed by inhalation to thermal degradation products from a rigid polyurethane foam degraded at 500.degree. C. All rats survived a 5-min exposure. Cytochrome c oxidase activity of heart and brain was noncompetitively inhibited as a result of exposure. The degree of inhibition was correlated with the concentration of blood cyanide within the concentration range of 0.1-1.1 .mu.g/ml. The mean blood cyanide concentration corresponding to 50% inhibition of the brain and heart enzymes was 0.28 .mu.g/ml. Liver cytochrome c oxidase activity showed a mild noncompetitive activation after a 5-min exposure. After a lethal exposure of approximately 8 min duration, liver cytochrome c oxidase activity was moderately inhibited in some but not in all animals.