CHEMOPREVENTIVE EFFECTS OF CABBAGE ON 7,12-DIMETHYLBENZ(A)ANTHRACENE-INDUCED HEPATOCARCINOGENESIS IN TOADS (BUFO-VIRIDIS)

Hepatocellular carcinoma was induced in the toad, Bufo viridis, in 29 out of 100 cases by the administration of 0.5 mg of 7,12-dimethylbenz( a)anthracene (DMBA)/toad, 3 times/week for 12 weeks. In contrast, toad s treated with DMBA and cabbage diet 1 or 2 ml (3 h prior to the carci nogen)/toad, every day for 12 weeks showed a lower incidence of liver tumors: 15 and 12 cases out of 100. However, cabbage diet (2 ml/toad, every day for 12 weeks) was ineffective when administered 3 h after th e carcinogen (DMBA) in 27 out of 100 cases. Neither tumor growth nor n eoplastic changes were observed in toads treated with olive oil alone or with cabbage diet. It is concluded that a cabbage diet during initi ation has an inhibitory effect on hepatocarcinogenesis in toads.