[Experimental heart tumours in rats (author's transl)]

In continuation of previous own investigations 68 heart tumours including 46 early stages were found in the heart of 590 BD IX rats systematically examined after treatment with methylnitrosourea (MNU) or ethylnitrosourea (ENU). The tumour incidence was about 40% in animals treated by repeated intravenous or intraperitoneal injections of 20 mg per kg body weight MNU. These experiments are suitable for the study of early stages and the histogenetic origin of heart tumours. At present MNU in addition to triazenes (table 5) belongs to the most powerful carcinogens which affect the heart in rats.