Regulation of glucagon-like peptide-1 synthesis and secretion in the GLUTag enteroendocrine cell line

Endocrinology. 1998 Oct;139(10):4108-14. doi: 10.1210/endo.139.10.6228.


Glucagon-like peptide-1 (GLP-1) released from the intestine is a potent stimulator of glucose-dependent insulin secretion. To elucidate the factors regulating GLP-1 secretion, we have studied the enteroendocrine GLUTag cell line. GLP-1 secretion was stimulated in a dose-dependent fashion by activation of protein kinase A or C with forskolin or phorbol 12,13-dibutyrate, respectively (by 2.3 +/- 0.5-fold at 100 microM and 4.3 +/- 0.6-fold at 0.3 microM, respectively; P < 0.01-0.001). Of the regulatory peptides tested, only glucose-dependent insulinotropic peptide stimulated the release of GLP-1 (by 2.3 +/- 0.2-fold at 0.1 microM; P < 0.001); glucagon was without effect, and paradoxically, the inhibitory neuropeptide somatostatin-14 increased secretion slightly (by 1.6 +/- 0.3-fold at 0.01 microM; P < 0.05). In tests of several neurotransmitters, only the cholinergic agonists carbachol and bethanechol stimulated peptide secretion in a dose-dependent fashion (by 2.3 +/- 0.5- and 1.7 +/- 0.3-fold at 1000 microM; P < 0.05-0.001); the beta-adrenergic agonist isoproterenol and the chloride channel inhibitor gamma-aminobutyric acid did not affect release of GLP-1. Long chain monounsaturated fatty acids (18:1), but not saturated fatty acids (16:0), also stimulated the release of GLP-1 (by 1.7 +/- 0.1-fold at 150 microM; P < 0.001). Consistent with the presence of a cAMP response element in the proglucagon gene, activation of the protein kinase A-dependent pathway with forskolin increased proglucagon messenger RNA transcript levels by 2-fold (P < 0.05); glucose-dependent insulinotropic peptide and phorbol 12,13-dibutyrate were without effect. Therefore, by comparison with results obtained using primary L cell cultures or in vivo models, GLUTag cells appear to respond appropriately to the regulatory mechanisms controlling intestinal GLP-1 secretion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carbachol / pharmacology
  • Cell Line
  • Cyclic AMP-Dependent Protein Kinases / physiology
  • Enteroendocrine Cells / metabolism*
  • Gastric Inhibitory Polypeptide / pharmacology
  • Glucagon / biosynthesis*
  • Glucagon / metabolism
  • Glucagon-Like Peptide 1
  • Mice
  • Peptide Fragments / biosynthesis*
  • Peptide Fragments / metabolism
  • Protein Kinase C / physiology
  • Protein Precursors / biosynthesis*
  • Protein Precursors / metabolism
  • Tetradecanoylphorbol Acetate / pharmacology


  • Peptide Fragments
  • Protein Precursors
  • Gastric Inhibitory Polypeptide
  • Glucagon-Like Peptide 1
  • Carbachol
  • Glucagon
  • Cyclic AMP-Dependent Protein Kinases
  • Protein Kinase C
  • Tetradecanoylphorbol Acetate