Res Exp Med (Berl) (1982) 180:155-159 Research in Experimental Medicine @ Springer-Verlag 1982 Alpha-Fetoprotein Dynamics During Ethionine-induced Hepatocarcinogenesis in Rat M. Miyazaki 1, S. Wahid l, K. Matsuura 1, and A. Watanabe 2 1Division of Pathology, Cancer Institute, and 2 1st Dept. of Internal Medicine, Okayama University Medical School, Okayama 700, Japan Summary. Rats fed on a diet containing 0.25% DL-ethionine (ethionine), which has been usually used as carcinogenic dose, demonstrated the early elevations of serum alpha-fetoprotein (AFP) approximately in week 6 of the feeding. After declining once between week 10 and week 14, the serum AFP levels increased again in week 22 of the continuous feeding, when well differentiated hepatocellular carcinoma had already developed. The level of serum AFP after development of hepatoma was found to be lower than those seen during the early elevation of AFP. Furthermore, in ethionine-induced hepatoma-bearing rats, AFP levels in the tumors were rather low as compared to those in the non- tumorous portions of the liver surrounding the tumors. The results indicate that ethionine-induced hepatocellular carcinoma is not an AFP-highly- producing tumor. Key words: Ethionine-induced hepatoma - AFP Introduction Ethionine, one of the drugs which are carcinogenic to rats, is well known to induce hepatocellular carcinoma exclusively [8]. We have already reported that the rapid and remarkable increase of AFP production during acute liver injury following a single injection of ethionine is closely associated with hepatic injury and is not the consequence of liver cell regeneration [11]. We have also reported that marked elevation of serum AFP concentrations following a single injection or chronic feeding of ethionine was prevented by giving methionine [6]. A number of investigators have reported that exposure to chemical hepato- carcinogens evoked a responsive synthesis of AFP [ 1,3, 4, 9]. However, the kinetic patterns of AFP production during hepatocarcinogenesis varied considerably according to the difference in type of the chemical hepatocarcinogens. For Offprint requests to: M. Miyazaki, MD (address see above) 0300-9130/82/0180/0155/$ 1.00