Synthesis of alpha-fetoprotein by rat ascites hepatoma cells

AH-66 rat ascites hepatoma cells incorporated [14C]leucine into the AFP fraction. In a cell-free system, hepatoma ribosomes were found to be active in AFP synthesis whereas the supernatant fraction from hepatoma had no specific effect on AFP production. The amount of [14C]leucine incorporated in AFP by membrane-bound polysomes was 20 to 90 times higher than that by free polysomes, suggesting that AFP is mainly synthesized on membrane-bound polysomes. DBcAMP inhibited the growth of hepatoma cells. However, the incorporation of [14C]leucine into the AFP fraction as well as into total proteins was stimulated by DBcAMP.