Gut Hormones
The gut is the largest endocrine organ of the body producing numerous peptide hormones. These are grouped into different families based upon homology as per the examples shown below and have numerous and diverse functions.
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Secretin Family – Including:
- Insulin Family – Including:
- EGF Family – Including:
- Epidermal Growth Factor and
- Transforming Growth Factor Alpha
- Gastrin Family – Including:
- Gastrin and
- Cholecystokinin
- PP Family – Including:
- Tachykinin Family – Including:
- Substance PNeurokinin A and
- Neurokinin B
- Somotostatin Family – Including:
- Somatostatin and
- Corticostatin
- Ghrelin Family – Including:
Those peptides involved in the regulation of appetite and satiety have become a focus for potential therapies in the fight against obesity and associated diseases.
GLP-1 is released by the intestine in response to food and stimulates secretion of insulin from the pancreas which enables the body to store and use the glucose produced by digestion. GLP-1 also acts via the vagal pathway to inhibit gastric acid secretion and gastric emptying which serve to increase satiety. Receptors for GLP-1 are also found in the brain, predominantly expressed in the Nucleus of the solitary tract and arcuate nucleus – regions associated with appetite and feeding behaviour. Analogues of GLP-1 such as Exendin-4, a peptide present in the venom of the Gila monster, have been keenly studied and are associated with weight loss.
Peptide YY (PYY), like GLP-1, is another member of the pancreatic peptide (PP) family and inhibits gastric secretion and gastric emptying. It too acts on receptors in the brain, binding the Y2 receptors on NPY neurons located in the arcuate nucleus. Like GLP-1, the PYY peptide has also proved of interest to those looking for anti-obesity therapies.
Associated links:
REVIEW: The anorectic gut hormones: GLP-1 and Co-Secreted peptide
GLP-1 Analogues
GLP-1 Analogues and Antagonists for Cell Biology
GLP-1 and Exendin-4 Antibody Product Focus
Glucagon-like peptides