Effect of diazepam on hepatocarcinogenesis in the rat.

The promotion effect of diazepam on the hepatocarcinogenesis initiated by 3'-methyl-4-(dimethyl-amino)azobenzene(3'-Me-DAB) in the rat was studied. Weanling rats were fed a diet containing 0.06% 3'-Me-DAB for 3 weeks, followed by either the basal diet or a diet containing 0.05% diazepam. The number and the size of enzyme-altered islands greater than 50 micrometers in diamter were scored at week 16. The feeding of diazepam did not increase the number and the size of enzyme-altered islands significantly, in comparison with those scored in animals fed 3'-Me-DAB alone. It was concluded that diazepam is not a promoter like phenobarbital in hepatocarcinogenesis.