Regulation of Hepatic Lipoprotein Receptors in the Dog. RAPID REGULATION OF APOLIPOPROTEIN B,E RECEPTORS, BUT NOT OF APOLIPOPROTEIN E RECEPTORS, BY INTESTINAL LIPOPROTEINS AND BILE ACIDS

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Abstract

Two distinct lipoprotein receptors can be expressed in the dog liver. One is the apolipoprotein (apo-) B,E receptor. This receptor binds apo-B-containing low density lipoproteins (LDL), as well as apo-E-containing lipoproteins, such as the cholesterol-induced high density lipoproteins (HDLc). The second hepatic lipoprotein receptor is the apo-E receptor. It binds apo-E HDLc and chylomicron remnants, but not LDL. The present studies were undertaken to determine whether short-term (acute) regulation of the two receptors can occur in response to perturbations in hepatic cholesterol metabolism. The design used three groups of experimental animals: (a) immature dogs (with both hepatic apo-B,E and apo-E receptors expressed), (b) adult dogs (with predominantly the apo-E receptor expressed and little detectable apo-B,E receptor binding activity), and (c) dogs treated with the bile acid sequestrant cholestyramine or those that have undergone biliary diversion (with apo-E receptors and induced apo-B,E receptors).

Authors

Bo Angelin, Carol A. Raviola, Thomas L. Innerarity, Robert W. Mahley