Gustducin couples fatty acid receptors to GLP-1 release in colon

Am J Physiol Endocrinol Metab. 2013 Mar 15;304(6):E651-60. doi: 10.1152/ajpendo.00471.2012. Epub 2013 Jan 22.

Abstract

Sweet taste receptor subunits and α-gustducin found in enteroendocrine cells of the small intestine have been implicated in release of the incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) in response to glucose and noncaloric sweeteners. α-Gustducin has also been found in colon, although its function there is unclear. We examined expression of α-gustducin, GLP-1, and GIP throughout the intestine. The number of α-gustducin-expressing cells and those coexpressing α-gustducin together with GLP-1 and/or GIP increased from small intestine to colon. α-Gustducin also was coexpressed with fatty acid G protein-coupled receptor (GPR) 40, GPR41, GPR43, GPR119, GPR120, and bile acid G protein-coupled receptor TGR5 in enteroendocrine cells of the colon. In colon, GPR43 was coexpressed with GPR119 and GPR120, but not with TGR5. Treatment of colonic mucosa isolated from wild-type mice with acetate, butyrate, oleic acid, oleoylethanolamide, or lithocholic acid stimulated GLP-1 secretion. However, GLP-1 release in response to these fatty acids was impaired in colonic tissue from α-gustducin knockout mice.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Colon / metabolism*
  • Fatty Acids, Nonesterified / metabolism
  • Gastric Inhibitory Polypeptide / metabolism
  • Glucagon-Like Peptide 1 / metabolism*
  • Heterotrimeric GTP-Binding Proteins / genetics
  • Heterotrimeric GTP-Binding Proteins / metabolism*
  • In Situ Hybridization
  • Intestinal Mucosa / metabolism*
  • Intestine, Small / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Receptors, G-Protein-Coupled / metabolism*
  • Signal Transduction

Substances

  • FFAR4 protein, mouse
  • Fatty Acids, Nonesterified
  • Ffar1 protein, mouse
  • Ffar2 protein, mouse
  • Gpbar1 protein, mouse
  • Gpcr41 protein, mouse
  • Gpr119 protein, mouse
  • Receptors, G-Protein-Coupled
  • Gastric Inhibitory Polypeptide
  • Glucagon-Like Peptide 1
  • GNAT3 protein, mouse
  • Heterotrimeric GTP-Binding Proteins