Glucagon-like peptide-1 receptor is present on human hepatocytes and has a direct role in decreasing hepatic steatosis in vitro by modulating elements of the insulin signaling pathway
✍ Scribed by Nitika Arora Gupta; Jamie Mells; Richard M. Dunham; Arash Grakoui; Jeffrey Handy; Neeraj Kumar Saxena; Frank A. Anania
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 538 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0270-9139
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✦ Synopsis
Glucagon-like peptide 1 (GLP-1) is a naturally occurring peptide secreted by the L cells of the small intestine. GLP-1 functions as an incretin and stimulates glucose-mediated insulin production by pancreatic beta cells. In this study, we demonstrate that exendin-4/GLP-1 has a cognate receptor on human hepatocytes and that exendin-4 has a direct effect on the reduction of hepatic steatosis in the absence of insulin. Both glucagon-like peptide 1 receptor (GLP/R) messenger RNA and protein were detected on primary human hepatocytes, and receptor was internalized in the presence of GLP-1. Exendin-4 increased the phosphorylation of 3-phosphoinositide-dependent kinase-1 (PDK-1), AKT, and protein kinase C zeta (PKC-zeta) in HepG2 and Huh7 cells. Small interfering RNA against GLP-1R abolished the effects on PDK-1 and PKC-zeta. Treatment with exendin-4 quantitatively reduced triglyceride stores compared with control-treated cells.
Conclusion:
This is the first report that the g protein-coupled receptor glp-1r is present on human hepatocytes. furthermore, it appears that exendin-4 has the same beneficial effects in vitro as those seen in our previously published in vivo study in ob/ob mice, directly reducing hepatocyte steatosis. future use for human nonalcoholic fatty liver disease, either in combination with dietary manipulation or other pharmacotherapy, may be a significant advance in treatment of this common form of liver disease.