[Comparison of the effect of different carcinogens on the skin of rats]

Solution of N-methyl-N-nitrosourea (MNU), diazoacetic ester (DAAE), N-methyl-N-nitro-N-nitrosoguanidine (MNNG), N-methyl-N,N'-dinitroguanidine, 4-dimethylaminoazobenzene (DAB), o-aminoazotoluene or 7,12-dimethylbenz(a)anthracene (DMBA) were applied to rat skin. Neoplasms (skin tumors) were found only in the experiments with MNU, DAAE, MNNG, DAB and DMBA, MNU, MNNG, DAB and DMBA induced tumours in the sites of skin painting. In experiments with DAAE distant skin neoplasms developed as well. Possible mechanisms of action of these compounds are discussed.