Insulin stimulates receptor-mediated uptake of apoE-enriched lipoproteins and activated α2-macroglobulin in adipocytes

Olivier Descamps, David Bilheimer, Joachim Herz

Research output: Contribution to journalArticle

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Abstract

The low density lipoprotein receptor-related protein (LRP) is a cell surface receptor that binds and internalizes several macromolecules including apolipoprotein E-enriched remnant lipoproteins and protease/antiprotease complexes such as activated α2-macroglobulin. Its function has been studied primarily in cultured fibroblasts and in liver. In the current studies, we provide evidence that LRP is present on the surface of primary adipocytes isolated from rat epididymal fat pads. The activity of the receptor increases 2-3-fold within minutes after the adipocytes are exposed to physiological concentrations of insulin as indicated by an increase in the uptake of 125I-labeled activated α2-macroglobulin. There is a corresponding increase in the uptake of [3H]cholesteryl esters from radiolabeled apoE-enriched β-very low density lipoprotein. The latter uptake was inhibited by an antibody against LRP and by a fusion protein containing the 39-kDa protein, also called receptor-associated protein, a known inhibitor of LRP function. In vivo, rats that had been fed ad libitum accumulated approximately 24-fold more chylomicron cholesteryl esters in their epididymal fat pads than did fasted control animals. We suggest that insulin stimulation of LRP, in a synergistic action with lipoprotein lipase, increases the endocytic uptake of cholesteryl esters and triglycerides from remnant lipoproteins in postprandial adipocytes.

Original languageEnglish (US)
Pages (from-to)974-981
Number of pages8
JournalJournal of Biological Chemistry
Volume268
Issue number2
StatePublished - Jan 15 1993

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Macroglobulins
Insulin Receptor
Apolipoproteins E
Adipocytes
Lipoproteins
Lipoprotein Receptors
Cholesterol Esters
Proteins
Adipose Tissue
Rats
LDL-Receptor Related Proteins
Insulin
Fats
Chylomicrons
VLDL Lipoproteins
Lipoprotein Lipase
LDL Receptors
Cell Surface Receptors
Protease Inhibitors
Fibroblasts

ASJC Scopus subject areas

  • Biochemistry

Cite this

Insulin stimulates receptor-mediated uptake of apoE-enriched lipoproteins and activated α2-macroglobulin in adipocytes. / Descamps, Olivier; Bilheimer, David; Herz, Joachim.

In: Journal of Biological Chemistry, Vol. 268, No. 2, 15.01.1993, p. 974-981.

Research output: Contribution to journalArticle

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