The effect of methionine on the progression of hepatocellular carcinoma induced by ethionine

Female Wistar rats were fed a semisynthetic diet containing 0.3% DL-ethionine for 52 weeks and, most of them bearing hepatocellular carcinomas, were switched to a basal diet for one week and then received 80 mg DL-methionine per rat (cir. 25 mg/100 g body wt) by gavage once per day, five times a week, over a period of 13 weeks. Methionine treatment significantly affected progression of hepatic tumors induced by DL-ethionine administration. The frequency of rats with hepatocellular carcinomas in the methionine treated group was significantly lower than that in control groups. It therefore appears that methionine treatment resulted in a remission of the malignant process.