[The relationship between cholesterol, shpingomyelin and phosphatidyl choline in liver and hepatoma cell membranes]

The cholesterol, sphingomyelin and phosphatidylcholine content in different cell membranes of liver and hepatoma was studied. Significant amounts of cholesterol were found in all the subcellular fractions of hepatoma, whereas in the liver cholesterol is localized mainly in the plasma membranes. A direct relation between the content of cholesterol and sphingomyelin was demonstrated. Possible effects of the cholesterol : : sphingomyelin : phosphatidylcholine ratio on the properties of cell membranes are discussed.