title: 3-Methylcholanthrene-inhibition of hepatocarcinogenesis in the rat due to 3'-methyl-4-dimethylaminoazobenzene or 2-acetylamino-fluorene: a comparative study.
abstract: Male Leeds strain rats were given a diet containing either 0.06% 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) or 0.05% 2-acetylaminofluorene (2-AAF), alone or together with 0.0067% 3-methylcholanthrene (MeCh). MeCh both reduced the incidence of hepatic neoplasms induced by 3'-MeDAB and delayed their development. With 2-AAF, however, inhibition of hepatocarcinogenesis by MeCh only appeared to operate during the period of treatment; thereafter the incidence of tumours rose rapidly and this was accentuated if dietary MeCh continued to be administered after the period of combined 2-AAF and MeCh treatment, suggesting a secondary, promoting effect of MeCH. In contrast, the inhibition by MeCh of carcinogenesis of Zymbal's gland due to 2-AAF was almost complete. Thus, in the long term MeCh has different effects upon 3'-MeDAB and 2-AAF carcinogenesis in the rat liver.
mesh_terms: D015073:2-Acetylaminofluorene / Q000037:antagonists & inhibitors*; D000818:Animals; D008113:Liver Neoplasms / Q000139:chemically induced* / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced* / Q000473:pathology; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology*; D008749:Methyldimethylaminoazobenzene / Q000037:antagonists & inhibitors*; D051381:Rats; D004124:p-Dimethylaminoazobenzene / Q000031:analogs & derivatives*
chemical_list: D008749:Methyldimethylaminoazobenzene; D008748:Methylcholanthrene; D015073:2-Acetylaminofluorene; D004124:p-Dimethylaminoazobenzene