Immunocytochemical evidence for a paracrine interaction between GIP and GLP-1-producing cells in canine small intestine

Cell Tissue Res. 1999 Nov;298(2):287-93. doi: 10.1007/s004419900093.


Glucagon-like-peptide 1 (GLP-1) released from the intestine is considered to be an important incretin. We have recently demonstrated that glucose-dependent insulinotropic peptide (GIP) stimulated GLP-1 secretion from canine ileal L cells in culture. To investigate further the interplay between GLP-1- and GIP-secreting cells, we set out to determine the exact location and abundance of both cell types throughout the canine intestine. Canine small intestine was subdivided into 15-20 segments and investigated by immunocytochemistry with computer-assisted imaging. The abundance of GIP-, GLP-1- and somatostatin-immunoreactive cells was determined. GIP-secreting K cells were equally distributed in duodenum and jejunum, with the GLP-1-secreting L cells concentrated in the jejunum (5% duodenum, 73% jejunum and 22% ileum). These results indicated that the middle section of the small intestine containing 69% of the K cells also contained 51% of the L cells. Double immunostaining confirmed this overlap and furthermore over 30% of the L cells in this region were found adjacent to K cells. These results suggest the existence of a paracrine interaction between the K and L cells and indicate the importance of the jejunum in the regulation of insulin release by enteric-derived incretins.

MeSH terms

  • Animals
  • Caenorhabditis elegans Proteins*
  • Dogs
  • Enteroendocrine Cells / metabolism
  • Female
  • Gastric Inhibitory Polypeptide / metabolism*
  • Immunohistochemistry
  • Intestine, Small / cytology
  • Intestine, Small / metabolism*
  • Killer Cells, Natural / metabolism
  • Male
  • Membrane Glycoproteins / metabolism*
  • Paracrine Communication*
  • Receptors, Notch
  • Somatostatin / metabolism
  • Somatostatin-Secreting Cells / metabolism
  • Tissue Distribution


  • Caenorhabditis elegans Proteins
  • Glp-1 protein, C elegans
  • Membrane Glycoproteins
  • Receptors, Notch
  • Somatostatin
  • Gastric Inhibitory Polypeptide