title: Reactive intermediates from nitrosamines.
abstract: Metabolism of N-nitrosodi-n-propylamine by isolated rat liver fractions yielded both n-propanol and isopropanol, providing evidence for a reaction sequence, initiated by formation of the alpha-hydroxynitrosamine, that leads to formation of carbonium ions. Administration of N-nitrosodi-n-propylamine to rats led to formation of 7-n-propylguanine but not 7-isopropylguanine in hepatic DNA, showing that in the intact cell, the reaction sequence is intercepted by nucleophilic sites in DNA before a carbocation is formed. Alkylation of DNA therefore appears to occur primarily by a bimolecular reaction not involving free alkyl cations. N-nitrosodi-n-propylamine is also oxidized by rat liver microsomes by two consecutive beta-oxidation reactions to yield N-nitroso-2-oxopropylpropylamine. The latter agent leads to production of 7-methylguanine and O6-methylguanine in liver DNA following its administration to rats. The chemical nature of the ultimate methylating agent is unclear.
mesh_terms: D000818:Animals; D001711:Biotransformation; D002273:Carcinogens / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008862:Microsomes, Liver / Q000378:metabolism; D009602:Nitrosamines / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D051381:Rats; D013329:Structure-Activity Relationship
chemical_list: D002273:Carcinogens; D009602:Nitrosamines; C013161:N-nitroso(di-n-propyl)amine; D012313:RNA; D004247:DNA