Mammals are incapable of the synthesis of certain polyunsaturated fatty aci
ds and must fulfil their needs from plant sources. These polyunsaturates ar
e further desaturated and chain elongated by the mammal, and quantitatively
the most important site is the liver. The enzymes concerned with this proc
ess are the desaturases and these have been shown to be lost with cell tran
sformation. We incubated normal human liver cells and a hepatoma cell line
with fatty acids of differing degrees of unsaturation and chain length, to
ascertain whether the transformed cells would exhibit the same response to
the fatty acids as the normal liver cells. There were no differences in the
way the two cell types reacted to the saturated fatty acid, but a mixed re
sponse to the monounsaturate. The two plant-derived polyunsaturates caused
more of the hepatoma cells to die, and this effect was more pronounced with
the longer chain move unsaturated compounds. The three fatty acids that ar
e precursors for eicosanoid synthesis showed the least effect on the normal
cells, but still caused hepatoma cell death to a degree very similar to th
at caused by the plant polyunsaturates.