Induction of carcinogenesis in Fischer rats by methylalkylnitrosamines.

Five nitrosomethyl-n-alkylamines with long aliphatic chains were administered to male F344 rats by gavage for 30 weeks. The rats treated with nitrosomethyl-n-octylamine and nitrosomethyl-n-nonylamine died within one year, while a majority of those given nitrosomethyl-n-decylamine, nitrosomethyl-n-dodecylamine, and nitrosomethyl-n-tetradecylamine lived for more than 80 weeks. Apart from the spontaneous tumors found in untreated rats of this strain, the rats treated with all four compounds containing an even number of carbon atoms in the long chain developed a high incidence of transitional cell carcinoma of the bladder. In addition, the rats treated with nitrosomethyloctylamine developed tumors of the liver (hepatocellular carcinomas and some angiosarcomas), lung, and nasal cavity. Nitrosomethylnonylamine failed to induce tumors in the bladder but induced tumors of the liver (hepatocellular carcinomas and cholangiocarcinomas), lung tumors, and some tumors of the nasal cavity.