Possible prevention by abieslactone of development of diethylnitrosamine-initiated GST-P positive foci in the rat liver

Triterpenoid compounds, isolated from plants of Abies genus (Pinceae), are known to exert anti-tumor promotion activities in mouse skin carcinogenesis . In the present study, we investigated whether AVB-1 and acid and acid met hyl ester derivatives have inhibitory effects on rat hepatocarcinogenesis b y using a liver medium-term bioassay for carcinogens (Ito's test), immunohi stochemically assessing the numbers and areas per cm(2) of preneoplastic le sions, glutathione S-transferase placental form (GST-P)-positive foci. In e xperiment 1, 6-week-old male Fisher 344 rats were given a single intraperit oneal injection of diethylnitrosamine (200 mg/kg b.w.) and subjected to two -thirds partial hepatectomy at week 3. From weeks 2 to 8, the compounds wer e given three times a week at a dose of 1 mg/kg b.w. by i.g. gavage and fou nd to significantly decrease the number of GST-P-positive foci in the liver . In experiment 2, AVB-1 was given three times a week at doses of 3, 1, or 0.3 mg/kg b.w. by i.g. gavage from weeks 2 to 8. All doses of AVB-1 signifi cantly decreased the numbers of GST-P-positive foci. Thus, our results sugg est that AVB-1 is a chemopreventive agent for rat hepatocarcinogenesis. (C) 2001 Wiley-Liss, Inc.