Bacterial metabolite S-equol modulates glucagon-like peptide-1 secretion from enteroendocrine L cell line GLUTag cells via actin polymerization

Biochem Biophys Res Commun. 2018 Jul 2;501(4):1009-1015. doi: 10.1016/j.bbrc.2018.05.100. Epub 2018 May 21.


S-equol is one of gut bacterial metabolites produced from soybean isoflavone daizein. While S-equol is known to promote glucose-induced insulin secretion from pancreatic β cells, whether S-equol affects glucagon-like peptide-1 (GLP-1) secretion from enteroendoceine L cells remains unclear. Here we assessed the effect of S-equol on GLP-1 secretion from mouse enteroendocrine L cell line GLUTag cells. GLUTag cells expressed GPR30 and estrogen receptors, which are putative S-equol receptors. Application of S-equol induced an increase in intracellular Ca2+ levels via GPR30. However, S-equol did not enhance GLP-1 exocytosis, and long-term treatment of S-equol suppressed GLP-1 secretion. Moreover, immunocytochemistry revealed that S-equol increased the density of cortical actin filaments via G12/13 signaling under GPR30. These data suggest that S-equol prevents GLP-1 secretion as a result of competing regulation between Ca2+ mobilization and actin reorganization.

Keywords: Actin reorganization; Bacterial metabolite; Enteroendocrine L cell; Glucagon-like peptide-1; Live-cell imaging; S-equol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism*
  • Animals
  • Bacteria / metabolism*
  • Calcium / metabolism
  • Cell Line
  • Enteroendocrine Cells / drug effects
  • Enteroendocrine Cells / metabolism*
  • Equol / pharmacology*
  • Exocytosis / drug effects
  • GTP-Binding Protein alpha Subunits, Gq-G11 / metabolism
  • Glucagon-Like Peptide 1 / metabolism*
  • Intracellular Space / metabolism
  • Mice
  • Polymerization*
  • Receptors, Estrogen / metabolism
  • Receptors, G-Protein-Coupled / metabolism


  • Actins
  • GPER1 protein, mouse
  • Receptors, Estrogen
  • Receptors, G-Protein-Coupled
  • Equol
  • Glucagon-Like Peptide 1
  • GTP-Binding Protein alpha Subunits, Gq-G11
  • Calcium