EFFECTS OF THE LIGNAN, ARCTIIN, ON 17-BETA ETHINYL ESTRADIOL PROMOTION OF PRENEOPLASTIC LIVER-CELL FOCI DEVELOPMENT IN RATS

Anti-promotional effects of arctiin, a lignan with anti-estrogenic act ion, against 17-beta ethinyl estradiol (EE) and 2-acetylaminofluorene (2-AAF) were examined using a medium-term liver bioassay based upon th e induction of glutathione S-transferase placental form (GST-P) positi ve foci in mt liver. Male F344 rats were initially injected with dieth ylnitrosamine (DEN, 200 mg/kg body weight) intraperitoneally and true weeks later were treated with arctiin (1%), EE (1.5 ppm or 5 ppm), 2-A AF (20 ppm), arctiin + EE (1.5 ppm or 5 ppm), or arctiin + 2-AAF (20 p pm) in the diet for 6 weeks and then killed, all rats being subjected to partial hepatectomy at week 3. EE and 2-AAF clearly increased the d evelopment of GST-P foci. Antipromotional effects of arctiin were obse rved only for 2-AAF. These findings provide experimental evidence that arctiin exerts weak-protective potential against hepatocarcinogenesis in rats.