title: Assay of some endogenous and synthetic sex steroids for tumor-initiating activity in rat liver using the Solt-Farber system.
abstract: Endogenous (estradiol-17 beta; progesterone) and synthetic (ethinyl estradiol; cyproterone acetate; norethindrone acetate; norethynodrel) sex steroids were evaluated for tumor-initiating activity in the rat liver using the Solt-Farber system. All steroids were negative. This provides further evidence that tumor formation in long-term rodent bioassays by these compounds may be due to epigenetic mechanisms.
mesh_terms: D000726:Androgen Antagonists / Q000633:toxicity; D000818:Animals; D002273:Carcinogens; D003534:Cyproterone / Q000031:analogs & derivatives / Q000633:toxicity; D017373:Cyproterone Acetate; D004958:Estradiol / Q000633:toxicity*; D004997:Ethinyl Estradiol / Q000633:toxicity*; D008113:Liver Neoplasms / Q000139:chemically induced* / Q000473:pathology; D008297:Male; D009374:Neoplasms, Experimental / Q000473:pathology; D009640:Norethindrone / Q000031:analogs & derivatives / Q000633:toxicity; D000077563:Norethindrone Acetate; D009641:Norethynodrel / Q000633:toxicity; D011374:Progesterone / Q000633:toxicity*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D000726:Androgen Antagonists; D002273:Carcinogens; D004997:Ethinyl Estradiol; D011374:Progesterone; D017373:Cyproterone Acetate; D004958:Estradiol; D009641:Norethynodrel; D000077563:Norethindrone Acetate; D003534:Cyproterone; D009640:Norethindrone