Cholesterol absorption and metabolism by the intestinal epithelium

This chapter discusses cholesterol absorption and metabolism by the intestinal epithelium. Cholesterol is essential for most mammalian cells where it is utilized either as a major structural component of membranes or as a substrate for the synthesis of more specialized sterols. Because of this critical role, mechanisms exist for maintaining cholesterol balance across the body so that the rate of sterol acquisition essentially equals the rate of sterol degradation and excretion, even under circumstances where there may be marked daily variation in the content of cholesterol in the diet. The intestinal mucosa plays a critical role in maintaining this balance because it is (1) the only site for absorption of dietary cholesterol, (2) one of the major organs involved in the de novo synthesis of cholesterol, and (3) essentially the only organ involved in the excretion of cholesterol and its metabolites. The chapter describes the central role of the intestinal epithelial cell in cholesterol metabolism and discusses the origin of the cholesterol in intestinal lymph.