GLP-1 secretion in response to oral and luminal palatinose (isomaltulose) in rats

J Nutr Sci Vitaminol (Tokyo). 2011;57(1):30-5. doi: 10.3177/jnsv.57.30.


Palatinose (isomaltulose), a slowly digested disaccharide, is used as a non-cariogenic sugar and as a sucrose substitute in several foods. Because of its ability to lower postprandial glycemia, palatinose may be beneficial as a treatment for impaired glucose metabolism. Glucagon-like peptide-1 (GLP-1) improves glycemia via enhancing pancreatic beta-cell functions. The secretion of GLP-1 is stimulated by sugars, including glucose and artificial sweeteners. In this study, we examined whether palatinose induced GLP-1 secretion in vivo and in vitro. Firstly, portal GLP-1 and glucose were measured after oral administration of palatinose or sucrose in conscious rats. Secondly, portal GLP-1 and glucose were measured after jejunal or ileal administration of each sugar in anesthetized rats. Finally, GLUTag, a murine GLP-1-producing cell line, was exposed to several sugars, including palatinose and sucrose, to observe the direct effect of these sugars on GLP-1 secretion. Compared with sucrose, palatinose enhanced portal GLP-1 level when administered orally in conscious rats. Both palatinose and sucrose induced a significant increase in portal GLP-1 after jejunal or ileal administration of each sugar in anesthetized rats. Ileal administration triggered a greater response than did jejunal administration. Glycemic responses were higher in sucrose-treated rats than in palatinose-treated rats in every experiment. In GLUTag cells, glucose induced a significant increase in GLP-1 secretion, but neither sucrose nor palatinose had an effect. These data demonstrate that luminal palatinose induces GLP-1 secretion in rats. However, it is likely that GLP-1 secretion is triggered mainly by glucose released in the lumen rather than by palatinose itself.

MeSH terms

  • Administration, Oral
  • Animals
  • Cell Line
  • Enteroendocrine Cells / metabolism
  • Glucagon-Like Peptide 1 / blood
  • Glucagon-Like Peptide 1 / metabolism*
  • Glucose / administration & dosage
  • Glucose / metabolism
  • Ileum / drug effects
  • Ileum / metabolism
  • Isomaltose / administration & dosage
  • Isomaltose / analogs & derivatives*
  • Isomaltose / metabolism
  • Jejunum / drug effects
  • Jejunum / metabolism
  • Male
  • Phenobarbital / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Sucrose / administration & dosage
  • Sucrose / metabolism
  • Sweetening Agents / administration & dosage*
  • Sweetening Agents / metabolism


  • Sweetening Agents
  • Sucrose
  • Isomaltose
  • Glucagon-Like Peptide 1
  • Glucose
  • isomaltulose
  • Phenobarbital