title: Tumor-initiating activity of the 9,10-dihydrodiol- and 9,10-dihydrodiol-7,8-epoxide of 3-methylcholanthrene in SENCAR mice.
abstract: The skin tumor-initiating activities of several bay-region metabolites of 3-methylcholanthrene (3-MCA) were determined in SENCAR mice. 3-MCA-anti-9,10-diol-7,8-epoxide possessed weak tumor-initiating activity when tested at 100 and 200 nmol/mouse doses (0.27 and 0.67 papillomas per mouse after 18 weeks of promotion with 12-O-tetradecanoylphorbol-13-acetate (TPA)). 3-MCA-trans-9,10-diol at initiating doses of 50 and 100 nmol/mouse was as active as 3-MCA. 3-MCA-trans-9,10-diol was also tested for mutagenic activity toward V79 cells in cell-mediated assays and found to be approximately 2-times more potent than 3-MCA. The data suggest that 3-MCA-trans-9,10-diol is a proximate carcinogen for mouse skin.
mesh_terms: D000818:Animals; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D008748:Methylcholanthrene / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity; D051379:Mice; D012878:Skin Neoplasms / Q000139:chemically induced*
chemical_list: D008748:Methylcholanthrene; C018600:methylcholanthrene-9,10-dihydrodiol; C038099:9,10-dihydroxy-7,8-epoxy-7,8,9,10-tetrahydro-3-methylcholanthrene; D004247:DNA