Pancreatic Glucagon-Like Peptide 1: What is known?

Genevieve Fava

doi:10.4172/2155-6156.1000397

Abstract

Glucagon-like peptide-1 (GLP-1) is an incretin hormone encoded together with glucagon by the proglucagon gene. It has been widely accepted that GLP-1 and glucagon are derived from distinct post-translational processing of proglucagon in a tissue specific manner. GLP-1 is produced in intestinal L-cells where proglucagon is processed by prohormone convertase 1/3 (PC1/3), while glucagon is produced in pancreatic α-cells via PC2-mediated cleavage. Nonetheless, emerging evidence has now demonstrated GLP-1 is also produced in pancreatic islets, although its concentration is much lower than glucagon. Further studies have shown GLP-1 production and secretion can be up-regulated by various factors, in particular, hyperglycemia and β-cell damage. The importance of locally produced GLP-1 in pancreas for β-cell function has started to be recognized. Similar to circulating GLP-1, α- cell produced GLP-1 can promote insulin secretion, protect β-cells and enhance β-cell proliferation, thus is vital for β-cell function. This review focuses on these recent discoveries regarding GLP-1 production in pancreatic islets and its action within pancreatic tissue.

Highlights

Glucagon-like peptide-1 (GLP-1) is one of the peptide hormones encoded by the proglucagon gene, which gives rise to a number of individual peptides through posttranslational processing [1,2,3,4,5]
This review focuses on recent discoveries on GLP-1 production in pancreatic islets and its action within pancreatic tissue
The production of glucagon is a result of PC2mediated cleavage of proglucagon in islet-resident α-cells, whereas the production of GLP-1 within intestinal L-cells is the result of prohormone convertase 1/3 (PC1/3) cleavage (Figure 1)

Summary

Introduction

Glucagon-like peptide-1 (GLP-1) is one of the peptide hormones encoded by the proglucagon gene, which gives rise to a number of individual peptides through posttranslational processing [1,2,3,4,5]. The production of GLP-1 within the pancreas in addition to intestinal L-cells has gained support from other studies. High glucose concentration and β-cell damage has been shown to stimulate GLP-1 secretion from cultured islets and allow it to be readily detected [45,48,49,52].

Results

Conclusion