Evidence Against the Presence of Hormone-Sensitive Lipase

Abstract Cholesteryl ester-laden macrophages are the hallmark of the fatty streaks that precede arteriosclerotic plaques in humans and experimental animals. This article studies several aspects of cytoplasmic cholesteryl ester metab-olism in cultured human monocyte-derived macrophages. Adenosine 3',5'-cyclic monophosphate (cAMP) consistently inhibited cholesteryl ester mobilization from cells that had been loaded with cholesteryl esters by preincubation with acetylated low-density lipoprotein. This effect was observed in both the absence and presence of extracellular cholesterol acceptors as well as with acyl coenzyme A:cholesterol acyl-transferase inhibitors. In contrast, dibutyryl cAMP activated cholesteryl ester hydrolysis in J774 macrophages. Since hor-mone-sensitive lipase is thought to be responsible for the neutral cholesteryl ester hydrolytic activity in several cel