Gastrointestinal peptides
The gastrointestinal hormones constitute a group of hormones secreted by enteroendocrine cells in the stomach, pancreas, and small intestine. This group of hormones regulate various functions of the digestive organs. Some of the major families are listed below.
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Gastrin–cholecystokinin family: gastrin (gastrin-34,"big gastrin"; gastrin-17, "little gastrin"; gastrin-14, "minigastrin") and cholecystokinin (CCK-58, CCK-33, CCK-22 and CCK-8)
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Secretin family: secretin, glucagon, vasoactive intestinal peptide and gastric inhibitory peptide
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Ghrelin, a growth hormone secretagogue synthesised by endocrine cells in the stomach, stimulates gastrointestinal motility like motilin agonists
| Hormone or peptide | Major tissue locations in the gut | Principal known actions |
|---|---|---|
| Bombesin: neuromedin B, gastrin releasing peptide | Throughout the gut and pancreas | Stimulate release of cholecystokinin (CCK) and gastrin |
| Calcitonin gene-related peptide: α-CGRP, β-CGRP | Enteric nerves | Unclear |
| Chromogranin A | Neuroendocrine cells | Secretory protein |
| Enkephalins | Stomach, duodenum | Opiate-like actions |
| Enteroglucagon | Small intestine, pancreas | Inhibits insulin secretion |
| Galanin | Enteric nerves | Unclear |
| Ghrelin | Stomach | Stimulates appetite, increases gastric emptying |
| Glucagon-like peptide 1 | Pancreas, ileum | Increases insulin secretion |
| Glucagon-like peptide 2 | Ileum, colon | Enterocyte-specific growth hormone |
| Growth factors | Throughout the gut | Cell proliferation and differentiation |
| Growth hormone-releasing hormone | Small intestine | Unclear |
| Leptin | Stomach | Appetite control |
| Motilin | Throughout the gut | Increases gastric emptying and small bowel motility |
| Neuropeptide Y | Enteric nerves | Regulation of intestinal blood flow |
| Neurotensin | Ileum | Affects gut motility; increases jejunal and ileal fluid secretion |
| Pancreatic polypeptide | Pancreas | Inhibits pancreatic and biliary secretion |
| Peptide YY | Colon | Inhibits food intake |
| Somatostatin: SRIF-28, SRIF-14 | Stomach, pancreas | Inhibits secretion and action of many hormones |
| Substance P | Enteric nerves | Unclear |
| Trefoil peptides: trefoil factor 1, trefoil factor 2, trefoil factor 3 | Stomach, intestine | Mucosal protection and repair |
Synthesis, secretion, and regulation of gastrointestinal peptides
Overview of gastrointestinal peptides in health and disease
A regularly updated and peer reviewed webpage summarising the role of GI peptides in health and disease, with links to additional webpages covering other relevant topics, e.g. physiology of gastrin, ghrelin, pancreatic polypeptide, peptide YY, and neuropeptide Y, insulin action and physiology of somatostatin and its analogues.
This regularly up-dated webpage provides a synopsis of the synthetic processes involved in production of gastrointestinal peptides, and regulation of these processes. Therapeutic implications are also briefly discussed.