Mutagenicity and alpha-hydroxylation of N-nitrosopyrrolidine and N-nitrosopiperidine: a possible correlation.

N-Nitrosopyrrolidine (NPyrr) and N-nitrosopiperidine (NPip) are carcinogenic and mutagenic cyclic nitrosamines. Their biotransformation by rat liver post-mitochondrial fraction into 1,4-butanediol and 1,5-pentanediol, respectively, is evaluated by determining these ultimate metabolites with a sensitive and suitable method. Their mutagenic activity towards the Salmonella typhimurium strain TA 1530 was simultaneously observed. A relationship exists between their metabolism and their mutagenicity. alpha-Hydroxylation is probably the critical metabolic metabolism of cyclic nitrosamines.