Tumor lipids: identification of sterol ester species in Ehrlich ascites cells.

The sterol ester fraction of Ehrlich ascites cell lipids was analyzed to determine: the type of sterol, the identity of the fatty acids esterified to the sterol, the presence or absence of carcinolipin, and the presence or absence of O-alkyl cholesteryl ethers. Gas-liquid Chromatographie analyses of the intact sterol esters and sterol derivatives showed the sterol to be cholesterol. The fatty acid esterified to cholesterol ranged in chain length from Ci4 to C24 and contained 0 to 6 double bonds. The major fatty acids were Ci6:0, C18:i, Ci8:2»Czo:4> and C22:6Carcinolipin, a branched-chain fatty acid ester of cholesterol, reported to be present at elevated levels in neoplasms, was not found. Chemical and Chromato graphie analyses failed to show the presence of O-alkyl cholesteryl ethers. The absence of cholesteryl ethers in this neoplasm which has been found to contain high levels of glyceryl ethers is of interest because normal tissues rich in glyceryl ether examined thus far contain cholesteryl ethers.