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Metabolism of acyclic and cyclic N-nitrosamines in cultured human bronchi
Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review
Curtis C. Harris, United States
Herman Autrup, Human Tissue Studies Section, Experimental Pathology Branch, Division of Cancer Cause and Prevention, NCI, National Institutes of Health, Public Health Service, U.S. Department of Health, Education, and Welfare, Bethesda, Maryland, Denmark
Gary D. Stoner, United States
Elizabeth M. McDowell, United States
Benjamin F. Trump, United States
Paul Schafer, United States
Institute of Environmental and Occupational Medicine
The metabolism of carcinogenic N-nitrosamines was studied in normal-appearing bronchial specimens obtained from 4 patients. Explants of bronchi were cultured in a chemically defined medium for 7 days. N-Nitrosamines [N-nitrosodimethylamine (DMN), N-nitrosodiethylamine (DEN), N,N'-dinitrosopiperazine (DNP), N-nitrosopyrrolidine (NPy), and N-nitrosopiperidine (NPd)] labeled with 14C were each then added at 100 mumoles for 24 hours. Measurable CO2 was formed by bronchial explants from: 1) DMN, DEN, and NPy in all 4 patients; 2) DNP in 3 of 4 patients; and 3) NPd in only 1 of 4 patients. In all bronchial specimens, these N-nitrosamines and/or their metabolites bound to bronchial mucosal DNA and protein. Binding levels were higher to protein than to DNA. Binding levels of DNP were as high as those with the two acyclic N-nitrosamines DMN and DEN, but binding levels of NPy and NPd were lower. Human bronchus was shown to metabolize and bind acyclic and cyclic N-nitrosamines found in the environment and in tobacco smoke.