Abstract
[C14]Dimethylnitrosamine was administered to rats, and the formation of free and protein-bound S-methylcysteine was investigated. Very little S-methylcysteine was found in liver acid-soluble fraction, in liver protein or in urine. The methylhistidines formed in liver protein were found to have largely disappeared by 6 days after injection of dimethylnitrosamine. The significance of these results in the carcinogenic action of dimethylnitrosamine is discussed.