Quantitative evaluation of genotoxic effects by molecular dosimetry.

The covalent binding of alkylating agents with DNA is considered a critical event in the mutagenic and carcinogenic effect of these chemicals. Several studies have indicated that only certain DNA alkylation products contribute to the mutagenic or carcinogenic activity of these agents. In this paper we summarize data obtained in Chinese hamster ovary (CHO) cells after treatment with two ethylating agents, N-ethylnitrosourea and diethylsulfate, which are known to alkylate DNA sites with different efficiency. A correlation study between DNA adduct formation and induction of mutations at two gene loci, i.e. hypoxanthine-guanine-phosphoribosyltransferase (HPRT) and Na,K-ATPase, has been performed. The influence of DNA repair processes on the final yield of mutation is specifically discussed.