• 1 January 1980
    • journal article
    • research article
    • Vol. 71  (6) , 755-758
Abstract
The mechanisms of inhibition by simultaneously administered phenobarbital of 3''-methyl-4-(dimethylamino)azobenzene (3''-Me-DAB)-induced hepatocarcinogenesis in the rat were studied. Weanling rats were fed a diet containing 0.06% 3''-Me-DAB or 0.06% 3''-Me-DAB and 0.05% phenobarbital for 3 wk, followed by a basal diet or a diet containing 0.05% phenobarbital as a promoter. The number and the size of enzyme-altered islands and the number of tumors larger than 5 mm in diameter were scored at 12 and 40 wk, respectively. The simultaneous feeding of phenobarbital and 3''-Me-DAB resulted in a significant decrease in the number and size of enzyme-altered islands and in the number of tumors, in comparison with those scored in animals fed 3''-Me-DAB alone. The simultaneous feeding of phenobarbital apparently inhibits the initiation of carcinogenesis and the promotive action of the carcinogen resulting from its selective toxicity on the liver tissue.