Properties of Intestinal Lipase

Abstract

Little is known regarding intestinal lipase, although its participation in the absorption of neutral fat from the gastrointestinal tract has been suggested (1). Lipolysis by intestinal enzymes was first established by Schiff (2) in studies with depancreatized dogs. Kalaboukoff and Terroine (3) later reported that glycerol extracts of intestinal mucosa hydrolyzed olive oil and that this activity was accelerated by the addition of bile salts. In this study, the lipase activity of intestinal mucosa has been examined. In order to limit the study to lipase activity, we have employed long chain triglycerides as substrate in the form of olive oil emulsions. As will be seen, the intestine also contains aliesterases, as judged by the rapid hydrolysis of short chain fatty acid esters. These enzymes would not be expected to interfere with lipase estimations, since, in other tissues such as the liver, they have been shown to be completely inactive toward long chain triglycerides. The pancreatic enzyme has generally been regarded as the prototype of lipases. We have therefore compared the intestinal and pancreatic enzymes with regard to substrate specificity and the effects of various activators and inhibitors, a number of which have been employed by other investigators to characterize esterolytic enzymes. Although the intestinal activity appears to be similar, in general, to that of the pancreas, it is clear that the enzymes involved are not identical. The possible participation of intestinal lipase in the intestinal absorption of fat is discussed.