Gastrointestinal and Pancreatic Neuroendocrine Cell Types and Secretory Products
| Cell type | Localization | Products |
| Delta | Entire gastrointestinal tract | Somatostatin |
| Enterochromaffin | Entire gastrointestinal tract | Serotonin/substance P/guanylin/melatonin |
| Enterochromaffinlike | Gastric fundus | Histamine |
| Gastrin | Gastric antrum and duodenum | Gastrin |
| Ghrelin | Entire gastrointestinal tract | Ghrelin |
| I | Duodenum | Cholecystokinin |
| K | Duodenum/jejunum | Gastric inhibitory peptide |
| L | Small intestine | GLP-1, PYY, NPY |
| Motilin | Duodenum | Motilin |
| Neurotensin | Small intestine | Neurotensin |
| Secretin | Duodenum | Secretin |
| Vasoactive intestinal peptide | Entire gastrointestinal tract | Vasoactive intestinal peptide |
| X | Gastric fundus and antrum | Amylin |
| Beta | Pancreas | Insulin |
| Alpha | Pancreas | Glucagon |
| Delta | Pancreas | Somatostatin |
| Pancreatic polypeptide | Pancreas | Pancreatic polypeptide |
GLP-1 = glucagonlike peptide 1; PYY = polypeptide YY (tyrosine, tyrosine); NPY = neuropeptide Y (tyrosine).