The organospecific activity of six n-nitroso compounds in the host-mediated assay with yeast and rats

The organospecific activity of the N-nitroso compounds diethylnitrosamine (DEN), dibutylnitrosamine (DBN), N-nitroso-piperidine, N-methyl-N-nitrosourethane (NMUT), N-methyl-N-nitroso-urea (NMU), and N-methyl-N'-nitro-N-Nitrosoguanidine (MNNG) has been studied in the host-mediated assay by recovering yeast cells present in testes, liver, and lung of rats. All six substances were genetically active, and their organospecificity under host-mediated assay conditions correspond relatively well to their organospecific carcinogenic effects of single dose experiments, but not to that of repeated administration. (ITA)