title: Role of nitrogen dioxide in the biosynthesis of nitraosamines in mice.
abstract: Groups of three to four mice were gavaged with aqueous solutions of 2 milligrams of morpholine, after which they were exposed to nitrogen dioxide in inhalation chambers at concentrations of 0.2 to 50 parts per million for up to 4 hours. At sequential intervals during the exposure, mice were frozen and pulverized in liquid nitrogen, and the mice powder was extracted with ice-cold 35 percent aqueous methanol and dichloromethane; organic-phase concentrates were analyzed for N-nitrosomorpholine with a thermal energy analyzer interfaced to a gas chromatograph. The N-nitrosomorpholine yields, ranging up to about 2.3 micrograms per mouse, were time-dependent relative to the duration of exposure to nitrogen dioxide and dose-dependent relative to the concentrations of nitrogen dioxide; control levels (in mice that were gavaged with morpholine or distilled water and then exposed to air instead of nitrogen dioxide) were less than 5 nanograms per mouse. These preliminary studies demonstrate the in vivo nitrosating potential of nitrogen oxides.
mesh_terms: D000588:Amines / Q000378:metabolism; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D001711:Biotransformation; D004305:Dose-Response Relationship, Drug; D051379:Mice; D009025:Morpholines / Q000378:metabolism*; D009585:Nitrogen Dioxide / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009602:Nitrosamines / Q000378:metabolism*; D013997:Time Factors
chemical_list: D000588:Amines; D009025:Morpholines; D009602:Nitrosamines; D001205:Ascorbic Acid; D009585:Nitrogen Dioxide