Abstract
Non polar, water-insoluble lipids, such as cholesterylesters and triglycerides, are transported in body fluids by plasma lipoproteins, which consist of a core of these hydrophobic lipids surrounded by phospholipids and free cholesterol and then by specific proteins (apoproteins).Plasma lipoproteins are classified into four large groups according to the size, density and composition of apoproteins. After their synthesis and secretion by the liver and intestine, lipoproteins are metabolized in circulation and taken up by the particular tissues, and the process is regulated by the apoproteins, related enzymes, and specific receptors for lipoproteins. These factors are very important to control the transport and metabolism of cholesterol and other lipids. In this review, the structure, function and metabolism of each of four types of lipoproteins are described. The factors that control the metabolism of lipoproteins are also discussed on a molecular basis.
