[Effect of alkylation and carbamoylation on the characteristics of genetic damage to mammalian somatic cells cultured in vitro].

Genetic effects of alkylation alone and combined with carbamoylation were studied following treatment of CHO-AT3-2 Chinese hamster cell line with N-nitroso-N-methylurea for 7 and 60 min. Gene mutations at HGPRT and Na+/K+-ATPase loci, micronuclei, cells with fragmented nuclei and lethality caused by NMU were recorded. Prolonged exposure to the mutagen made these effects more pronounced, particularly the fragmented nuclei and cell death. The combined action of the two mechanisms, therefore, enhanced the mutagenic effects of alkylation and expanded the range of DNA lesions towards greater incidence of gross damage to chromosomes and chromatids.