Mouse Mammary Carcinogenesis by Ethyl and Butyl Carbamates

Experiments examining the effect of ethyl carbamate and butyl carbamate on mammary carcinogenesis are reported. Virgin female C3H mice receiving ethyl carbamate or butyl carbamate showed a higher incidence of tumors than the controls. The action of ethyl carbamate was the same when given in massive or fractionated dose but a massive dose shortened the latent period of tumor development. Simultaneous administration of ethyl carbamate and butyl carbamate had a summational effect. Administration of croton oil to animals receiving ethyl carbamate did not provoke the appearance of skin tumors. A higher number of metastases was observed in animals bearing breast tumors when ethyl carbamate or butyl carbamate was administered.