title: High incidence of hepatocellular carcinomas after synthetic estrogen administration in Syrian golden hamsters fed alpha-naphthoflavone: a new tumor model.
abstract: P8 80-100% incidence of multinodular hepatocellular carcinomas was observed in castrated male hamsters following synthetic estrogen treatment in the presence of 0.2-0.4% alpha-naphthoflavone (ANF) in the diet after 8.5-10 months. Induction of these liver tumors was detected as early as 3.5-4.0 months in low frequency. Of the synthetic estrogens studied, ethynylestradiol (CAS: 57-63-6) was a more potent inducer of these hepatic carcinomas than either diethylstilbestrol (CAS: 56-53-1) or hexestrol (CAS: 84-16-2). ANF, considered an inhibitor of P450-dependent multisubstrate monooxygenases, did not produce any liver tumors when administered alone for up to 12 months. Neither concomitant androgen nor progesterone (CAS: 57-83-0) treatment resulted in any hepatic carcinomas in animals maintained on ANF. Moreover, beta-naphthoflavone (CAS: 6051-87-2) treatment alone or in combination with these synthetic estrogens also resulted in no hepatic tumors. This new estrogen-induced liver tumor model could be useful to elucidate the casual relationship that exists between estrogenic hormones and hepatic tumors in humans.
mesh_terms: D000818:Animals; D001571:Benzoflavones / Q000633:toxicity*; D006224:Cricetinae; D004054:Diethylstilbestrol / Q000633:toxicity; D004195:Disease Models, Animal; D045166:Estradiol Congeners / Q000633:toxicity*; D004997:Ethinyl Estradiol / Q000633:toxicity; D005419:Flavonoids / Q000633:toxicity*; D006589:Hexestrol / Q000633:toxicity; D007680:Kidney Neoplasms / Q000139:chemically induced / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000473:pathology*; D008647:Mesocricetus; D011374:Progesterone / Q000494:pharmacology; D013997:Time Factors
chemical_list: D001571:Benzoflavones; D045166:Estradiol Congeners; D005419:Flavonoids; D006589:Hexestrol; D004997:Ethinyl Estradiol; D011374:Progesterone; C011512:alpha-naphthoflavone; D004054:Diethylstilbestrol