Effect of methylnitrosocyanamide on cultured mammalian cells.

Effect of methylnitrosocyanamide (MNC) on a cultured mammalian cell line was examined in comparison with that of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). It was observed that MNC was about 3 times more potent than MNNG in the experiments on toxicity and inducibility of chromosome aberration and mutation. An increase in toxicity of MNNG was observed by minimizing the elevation of pH, while toxicity of MNC was more potent in the serum-free condition than in the presence of serum. Further, MNC was shown to be extremely rapid-acting, that is, 10 min was enough to exert its toxic effect.