title: D-glucose releases 5-hydroxytryptamine from human BON cells as a model of enterochromaffin cells.
abstract: OBJECTIVE
  5-Hydroxytryptamine (5-HT) is released from enterochromaffin cells and activates neural reflex programs regulating motility and secretion. Although sugars are reported to release 5-HT in vivo, it is unclear whether they act directly on enterochromaffin cells or indirectly through an intermediary messenger. The aim was to determine if D-glucose is a stimulus for 5-HT release.
  
  
  METHODS
  Human BON cells, derived from enterochromaffin cells, were treated with D-glucose, galactose, and the nonmetabolizable methyl alpha-D-glucopyranoside, or with fructose.
  
  
  RESULTS
  Reverse-transcription polymerase chain reaction together with Western blot analysis revealed an SGLT-like protein. D-glucose caused a concentration-dependent increase in 5-HT release, which was mimicked by methyl alpha-D-glucopyranoside and galactose but not fructose. D-glucose-stimulated 5-HT release was significantly reduced by phloridzin. Concentrations of mannitol below 75 mmol/L were ineffective in releasing 5-HT. Brefeldin A abolished forskolin-stimulated 5-HT release without affecting basal or constitutive release.
  
  
  CONCLUSIONS
  The results show that high concentrations of metabolizable and nonmetabolizable hexoses activate signal transduction pathways, leading to release of 5-HT. These findings imply a role for enterochromaffin cells as "glucose sensors" during ingestion of a meal.
authors.affiliation: Department of Pharmacology, The Ohio State University, 333 West 10th Avenue, Columbus, OH 43210, USA.
authors.forename: M
authors.initials: M
authors.lastname: Kim
authors.forename: H J
authors.initials: HJ
authors.lastname: Cooke
authors.forename: N H
authors.initials: NH
authors.lastname: Javed
authors.forename: H V
authors.initials: HV
authors.lastname: Carey
authors.forename: F
authors.initials: F
authors.lastname: Christofi
authors.forename: H E
authors.initials: HE
authors.lastname: Raybould
mesh_terms: D020126:Brefeldin A / Q000494:pharmacology; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D004759:Enterochromaffin Cells / Q000187:drug effects* / Q000378:metabolism*; D005632:Fructose / Q000494:pharmacology; D005690:Galactose / Q000494:pharmacology; D015870:Gene Expression; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D008353:Mannitol / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008757:Methylglucosides / Q000494:pharmacology; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D010695:Phlorhizin / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism*; D051269:Sodium-Glucose Transporter 1
chemical_list: D008562:Membrane Glycoproteins; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D051269:Sodium-Glucose Transporter 1; D005576:Colforsin; D020126:Brefeldin A; D005632:Fructose; D012701:Serotonin; D008353:Mannitol; C027020:methylglucoside; D010695:Phlorhizin; D005947:Glucose; D005690:Galactose