Biochemical Aspects of Fat Absorption

Abstract

In considering the mechanisms involved in the absorption and transport of lipids, we must consider the maj or constituents which are normally presented to the intes­ tinal mucosal cell following the ingestion of a fatty meal. As has been amply demon­ strated (and discussed by Dr. Hofmann in one of the earlier presentations today), the ingestion of triglyceride is normally fol­ lowed by extensive intraluminal lipolysis. This process is catalyzed by pancreatic lipase in the presence of bile salts. The fatty acids and monoglycerides which are produced find themselves to a large extent in the form of mixed micelles with bile salts. I would like to concentrate on the subsequent fate of these fatty acids and monoglycerides. It has been amply demonstrated that, in the transport of long chain fatty acids and monoglycerides across the intestinal muco­ sal cell, re-esterification to triglycerides is essential. The esterification mechanism applies primarily to the fatty acids that contain greater than 10 carbon atoms. As will be mentioned subsequently, in the case of shorter or medium chain fatty acids es­ terification is not obligatory and the trans­ port pathways of medium chain and long chain fatty acids are thus quite different. One of the key steps in the esterification reaction in the intestinal mucosa is the Presented at the Symposium of the Gastro­