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Symbol Motilin_ghrelin
Pfam PF04644
InterPro IPR006738
SCOP 1lbj
OPM family 154
OPM protein 1lbj
Available PDB structures:

1lbjA:27-47 1p7xA:24-51

Symbol MLN
Entrez 4295
HUGO 7141
OMIM 158270
RefSeq NM_001040109
UniProt P12872
Other data
Locus Chr. 6 p21.3-p21.2

Motilin is a polypeptide hormone secreted by Mo cells of the small intestine that increases the migrating myoelectric complex component of gastrointestinal motility and stimulates the production of pepsin. Control of motilin secretion is largely unknown, although some studies suggest that an alkaline pH in the duodenum stimulates its release. Interestingly however, at low pH it inhibits gastric motor activity, whereas at high pH it has a stimulatory effect.

Apart from in humans, motilin receptors are found in pigs', rats',cows' and cats' gastrointestinal tracts and in rabbits' central nervous systems.

Motilin agonists

Erythromycin and related antibiotics act as non-peptide motilin agonists, and are sometimes used for their ability to stimulate gastrointestinal motility. Administration of a low dose of erythromycin will induce peristalsis, which provides additional support for the conclusion that motilin secretion triggers this pattern of gastrointestinal motility, rather than results from it. However, some of erythromycin’s properties, including antibiotic activity, are not appropriate for a drug designed for chronic use over a patient's lifetime.

New motilin agonists are erythromycin based, however, it may be that this class of drugs becomes redundant; growth hormone secretagogue receptors share 52% of their DNA with motilin receptors and agonists of these receptors, termed ghrelins, can bring about similar effects to motilin agonists.

Related peptides

This domain is also found in ghrelin, a growth hormone secretagogue synthesised by endocrine cells in the stomach. Ghrelin stimulates growth hormone secretagogue receptors in the pituitary. These receptors are distinct from the growth hormone-releasing hormone receptors, and thus provide a means of controlling pituitary growth hormone release by the gastr ointestinal system[1].


  1. ^ Kangawa K, Matsuo H, Kojima M, Hosoda H (2001). "Ghrelin: discovery of the natural endogenous ligand for the growth hormone secretagogue receptor". Trends Endocrinol. Metab. 12 (3): 118-122. PMID 11306336.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Motilin". A list of authors is available in Wikipedia.
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