Abstract: The purpose of this study was to investigate the inhibition effect of DNA synthesis and the AFP secretion on BEL - 7402 human hepatocarcinoma cells in the presence of linolenic acid ,linoleic acid and oleic acid which having the same carbon chains. The AFP concent ration was determinated with radioimmunoassay ,while the DNA synthesis was studied by the 3 H - TdR incorporation (CPM) . The result sindicated that three f ree fatty acids could inhibite the DNA synthesis of human hepatocarcinoma cells. The effect s of linolenic acid and linoleic acid( P < 0. 01) were significant ,which were st ronger than that of oleic acid ( P > 0. 05) . 40 - 50μg/ ml concent ration of linolenic acid could inhibite the AFP secretion of hepatocarcinoma cells obviously compare with the blank ( P < 0. 05) . The same concent ration of linoleic acid and oleic acid had no difference compare with the blank ( P > 0. 05) . The conclusion showed that there was a relationship between the molecular st ructure and the inhibition effect s of three fatty acids containing different numbers of double - bond.

Key words: linolenic acid, linoleic acid, oleic acid, human hepatocarcinoma cell, AFP secretion