LDL-cholesterol levels are determined by the relative rates of input and removal of this class of lipoprotein from plasma. Removal of LDL occurs primarily via LDL receptors in the liver. Hepatocytes derive their cholesterol from exogenous sources via the LDL receptor, and by endogenous synthesis from HMG CoA. A major use of cholesterol by the liver is for the synthesis of bile acids, which undergo enterohepatic circulation after secretion into the intestinal tract (Fig. 6.34a).
