Abstract
The xanthoma tissue was minced and then extracted with 20 volumes of chloroform-methanol (2: 1) mixture. The yield of crude lipid was 1.25g from 8.0g of the tumor. Crude lipid was fractionated on a silicic acid column into the following: cholesteryl ester, triglyceride, cholesterol, and phospholipid.
It was notable that a larger amount of cholesteryl ester was found in the xanthoma lipid than cholesterol in it. A C15 fatty acid was detected among fatty acids of cholesteryl ester of the tumor tissue. Fatty acids of triglyceride in the tumor tissue, too, were gas-chromatographically analyzed and a similar composition to those of the normal serum was found.
Phospholipid of the tumor tissue was found to be consisted mainly of phosphatidylethanolamine (PE), phosphatidylcholine (PC), and sphingomyelin. A larger amount of phosphorus of PE was determined than that of the normal serum and that of PC was less.
It was interesting that occurrence of cholesta-3, 5-dien was detected in the tumor lipid, though it is still obscure whether its occurrence in the xanthoma tissue is physiological or not. When cholesteryl stearate was hydrolyzed by cholesterol esterase of rat liver in vitro, production of cholesta-3, 5-dien, bischolesteryl ether and bischolestadien was detected besides cholesterol as the main hydrolysate.
