title: Comparison of the skin tumor initiating activity of 3-methylcholanthrene and 3,11-dimethylcholanthrene in mice.
abstract: The abilities of 3-methylcholanthrene (3-MC) and 3,11-dimethylcholanthrene (3,11-DMC) to initiate skin tumors in Sencar mice were determined by using a 2-stage system of tumorigenesis. 3,11-DMC was found to have very weak skin tumor initiating activity when compared to the potent activity of 3-MC. The only difference between 3-MC and 3,11-DMC is the substitution of a methyl group in position 11 which is part of the 'K-region' or the 'peri' position. From these results, we suggest that an unhindered peri position adjacent to an angular benzene ring is necessary for carcinogenic activity of 3-MC.
mesh_terms: D000818:Animals; D005260:Female; D008748:Methylcholanthrene / Q000031:analogs & derivatives* / Q000633:toxicity*; D051379:Mice; D009374:Neoplasms, Experimental / Q000139:chemically induced; D010212:Papilloma / Q000139:chemically induced*; D012878:Skin Neoplasms / Q000139:chemically induced*; D013329:Structure-Activity Relationship; D013755:Tetradecanoylphorbol Acetate / Q000008:administration & dosage
chemical_list: D008748:Methylcholanthrene; C020892:3,11-dimethylcholanthrene; D013755:Tetradecanoylphorbol Acetate