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The Metabolic Role of Lecithin: Cholesterol Acyltransferase: Perspectives from Pathology

1973; Elsevier BV; Linguagem: Inglês

10.1016/b978-0-12-024911-4.50008-8

0065-2849

John A. Glomset, Kaare R. Norum,

Lipid metabolism and biosynthesis

This chapter discusses the metabolic role of enzyme lecithin called cholesterol acyltransferase (LCAT). The role of the LCAT reaction is to prevent unesterified cholesterol, derived mainly from the surfaces of chylomicrons and very low density lipoproteins, from accumulating in the plasma. This is successfully accomplished only when the LCAT reaction balances the mechanisms that increase plasma unesterified cholesterol. A balance does not occur in familial LCAT deficiency because the enzyme is absent. It does not occur in cholesterol-fed guinea pigs because unusually large amounts of dietary unesterified cholesterol enter the plasma through inadequate control in either the intestine or the liver. It does not occur in cholestasis because phospholipid bilayers are formed and promote the accumulation of unesterified cholesterol in plasma through increased hepatic biosynthesis. Unesterified cholesterol becomes associated with the surfaces of newly formed lipoproteins by physical equilibration within the cells of the intestinal mucosa and the liver. The function of the LCAT reaction is to transport unesterified cholesterol synthesized in peripheral tissues to the liver.