Metabolic fate of n-methyl-N-dodecylnitrosamine in the rat, in relation to its carcinogenicity to the urinary bladder.

The metabolic fate of N-methyl-N-dodecylnitrosamine (MDN) was investigated in the rat, in order to elucidate a possible correlation between urinary metabolites and organotropic carcinogenicity to the urinary bladder of this N-nitrosamine. MDN was extensively metabolized in the rat, no unchanged MDN being found in the urine. The urinary metabolites identified were N-methyl-N-(3-carboxypropyl) nitrosamine (MCPN), N-methyl-N-(2-hydroxy-3-carboxy-propyl) nitrosamine, N-methyl-N-(carboxymethyl) nitrosamine, and N-methyl-N-(2-oxopropyl) nitrosamine. Thus the metabolic pattern of MDN was essentially similar to that of N-methyl-N-(4-hydroxybutyl) nitrosamine, a potent bladder carcinogen, in the rat. A possible important role of MCPN in the induction of bladder tumors by MDN is discussed.