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Mol Cell Endocrinol. 2011 Aug 22;343(1-2):71-8. doi: 10.1016/j.mce.2011.06.008. Epub 2011 Jun 15.

Postprandial triglyceride-rich lipoproteins induce hepatic insulin resistance in HepG2 cells independently of their receptor-mediated cellular uptake.

Author information

1
Department of Internal Medicine I, Medical University of Innsbruck, Anichstrasse 35, A-6020 Innsbruck, Austria.

Abstract

Non-alcoholic fatty liver disease (NAFLD) is associated with hepatic insulin resistance with the molecular basis of this association being not well understood. Here we studied the effect of hepatic triglyceride accumulation induced by postprandial triglyceride-rich lipoproteins (TGRL) on hepatic insulin sensitivity in HepG2 cells. Incubation of HepG2 cells with purified TGRL particles induced hepatocellular triglyceride accumulation paralleled by diminished insulin-stimulated glycogen content and glycogen synthase activity. Accordingly, insulin-induced inhibition of glycogen synthase phosphorylation as well as insulin-induced GSK-3 and AKT phosphorylation were reduced by TGRL. The effects of TGRL were dependent on the presence of apolipoproteins and more pronounced for denser TGRL. Moreover, TGRL effects required the presence of heparan sulfate-proteoglycans on the cell membrane and lipase activity but were independent of the cellular uptake of TGRL particles by receptors of the LDL receptor family. We suggest postprandial lipemia to be an important factor in the pathogenesis of NAFLD.

PMID:
21704120
PMCID:
PMC3167371
DOI:
10.1016/j.mce.2011.06.008
[Indexed for MEDLINE]
Free PMC Article

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