[Induction by dimethylnitrosamine of mutants resistant to diphtheria toxin in human cells]

Stable spontaneous mutants resistant to the protein synthesis inhibitor diphtheria toxin have been selected in human cell line EUE at a very low frequency (less than 8 x 10-6). We have assayed in this system the mutagenic activity of dimethylnitrosamine (DMNA): mutation increases by this compound have been used as an estimate of his mutagenic activity. Treatment of cells with this compound increased the frequency of diphtheria toxin resistant mutants only at the highest dose used (10-1 M).