title: Denitrosation of N-nitrosomorpholine by liver microsomes; possible role of cytochrome P-450.
abstract: Liver microsomes from male mice and rats were incubated with N-nitrosomorpholine (MoNA) and an NADPH-regenerating system. The formation of nitrite was measured after induction or inhibition of the microsomal monooxygenase system. Pretreatment of the animals with phenobarbital (PB) enhanced nitrite formation by about 200%, while 3-methylcholanthrene (3-MC)-induction showed no exceptional effects. Various specific inhibitors of the monooxygenase function including carbon monoxide decreased nitrite formation. In conjunction with results obtained by spectra studies it is suggested that N-nitrosomorpholine is denitrosated by a reduction process in which cytochrome (cyt.) P-450 seems to be involved. Nitricoxide formed is partly converted to nitrite under these conditions.
mesh_terms: D000607:Aminoacetonitrile / Q000494:pharmacology; D000818:Animals; D001571:Benzoflavones / Q000494:pharmacology; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D008658:Inactivation, Metabolic; D007700:Kinetics; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D051379:Mice; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D009025:Morpholines / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D009602:Nitrosamines / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats
chemical_list: D001571:Benzoflavones; D065607:Cytochrome P-450 Enzyme Inhibitors; D009025:Morpholines; D009573:Nitrites; D009602:Nitrosamines; D000607:Aminoacetonitrile; C002741:N-nitrosomorpholine; D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D010634:Phenobarbital