The metabolism of N-nitrosomethylaniline.

The distribution in the body, rate of disappearance from organs, tissues, and blood, and excretion in the urine of N-nitrosomethylaniline (NMA, N-nitrosophenylmethylamine) was investigated after various single doses given IP to rats. The compound was distributed fairly evenly throughout the body with no preferential concentration in the esophagus, its target organ for carcinogenicity. The high lipid solubility of NMA did not lead to any increased accumulation in adipose tissue. According to its rate of disappearance from circulating blood and tissues of rats, and from the whole bodies of mice after injection, NMA appeared to be rapidly metabolized. Methylaniline (MA), the parent amine, was found in the urine after administration of NMA but the amounts present were small relative to the dose of NMA. Administered MA was mainly excreted unchanged in the urine, suggesting that denitrosation of NMA could only be a minor metabolic pathway. No volatile nitrosamines were found in the urine or blood of rats given NMA, indicating that little, if any, transnitrosation could have occurred to yield these compounds.