The influence of diazepam and thiouracil upon the carcinogenic effect of diethylnitrosamine in gerbils

N-diethylnitrosamine (DEN) was simultaneously administered with diazepam (DZP) or thiouracil (TU) once weekly for life to gerbils (Meriones unguiculatus). Additional DZP or TU treatment increased significantly average survival time and inhibited the development of cholangiocarcinomas, although cholangiomas were still observed in these groups. Tumor type and incidence in the nasal cavities were not influenced by DZP or TU. However, in comparison to DEN alone tumor latencies were prolonged.