Cholesteryl ester synthesis in canine vein and artery

Accumulation of cholesteryl esters in arterial tissue is a prominent feature of human and experimental atherosclerosis. This accumulation does not occur in undisturbed venous tissue, but has been reported in veins which have been surgically placed into the arterial system as bypass grafts. The formation of cholesteryl esters and some properties of the fatty acyl-CoA:cholesterol acyltransferase system have been studied in microsomal preparations from canine arterial and venous tissue. The rate of synthesis of cholesteryl palmitate was five-fold faster in venous than in arterial preparations. There was no difference, however, in the apparent Km values. Our results indicate that venous tissue possesses active fatty acyl-CoA:cholesterol acyltransferase activity which may be partly responsible for the accumulation of cholesteryl esters in veins grafted into the arterial system.