title: 12-O-tetradecanoylphorbol-13-acetate promotes tumors prior to initiation in two-stage promotion.
abstract: The tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) and the non-promoter mezerein both induce ornithine decarboxylase activity in mouse epidermis by a route which can be blocked by indomethacin. In two-stage tumor promotion experiments in mice with mezerein as the stage II promoter, TPA was effective as the stage I promoter whether it was applied before or after an initiating dose of 7,12-dimethylbenz[a]anthracene (DMBA). There appear to be at least 4 events in promotion, only 3 of which are caused by second stage promoters.
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D002273:Carcinogens / Q000633:toxicity; D003043:Cocarcinogenesis; D004224:Diterpenes; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D051379:Mice; D008954:Models, Biological; D009955:Ornithine Decarboxylase / Q000378:metabolism; D065108:Ornithine Decarboxylase Inhibitors; D010212:Papilloma / Q000139:chemically induced* / Q000201:enzymology; D010704:Phorbols / Q000633:toxicity*; D012878:Skin Neoplasms / Q000139:chemically induced* / Q000201:enzymology; D013729:Terpenes / Q000633:toxicity; D013755:Tetradecanoylphorbol Acetate / Q000633:toxicity*; D013997:Time Factors
chemical_list: D002273:Carcinogens; D004224:Diterpenes; D065108:Ornithine Decarboxylase Inhibitors; D010704:Phorbols; D013729:Terpenes; C011309:mezerein; D015127:9,10-Dimethyl-1,2-benzanthracene; D009955:Ornithine Decarboxylase; D013755:Tetradecanoylphorbol Acetate