||Biosynthesis of Dimethylnitrosamine in Dimethylamine-Treated Mice After Exposure to Nitrogen Dioxide.
Iqbal, Zafar M. ;
Dahl, Kristine ;
Epstein, Samuel S. ;
||Illinois Univ. at the Medical Center, Chicago.;Health Effects Research Lab., Research Triangle Park, NC.
Nitrogen dioxide ;
Laboratory animals ;
Nitrogen organic compounds ;
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These studies demonstrate the nitrosating potential of NO2 in vivo in 1CR mice. Groups of mice were gavaged with 2 mg dimethylamine (DMA) and exposed to NO2 at levels from 0.04 to 44.5 ppm for periods up to 4 hours. Mice were individually frozen and blended to a powder, aliquots of which were homogenized in ice-cold dichloromethane and 35% aqueous methanol. Concentrates of organic extracts were analyzed for dimethylnitrosamine (DMN) by a Thermal Energy Analyzer with a gas chromatograph interface. Biosynthesis of DMN was dose- and time-dependent with relation to NO2 exposure, reaching a maximum yield of 60-70 ng/mouse (0.0034% DMA conversion) at 2 hours. DMN biosynthesis was inhibited by sodium ascorbate and, more effectively, by ammonium sulfamate.