Abstract

The biological fate of nitrosamines, known as environmental carcinogens, and their metabolic activation in biological system are reviewed. This article includes the absorption, distribution, metabolism and excretion of dimethylnitrosamine, alkylation of nucleic acid bases with nitrosamines, metabolic activation of dialkylnitrosamines to produce alkyl cations as alkylating agents via α-hydroxylation, and the effects of substituents of α-carbon of dialkylnitrosamines on their biological activities. Emphasis has been placed to α-acetoxyalkylnitrosamines as masked compounds of α-hydroxylated active species. Their chemistry, carcinogenicity, and mutagenicity are compared. Organospecific carcinogenicity of dibutylnitrosamine and N-butyl-N-(4-hydroxybutyl) nitrosamine, urinary bladder carcinogens, are explained in terms of metabolism and metabolic activation.