Motilin: a panoply of communications between the gut, brain, and pancreas

ABSTRACT

Introduction: Motilin was first alluded to nearly a century ago. But it remains a rather abstruse peptide, in the shadow of its younger but more lucid ‘cousin’ ghrelin.

Areas covered: The review aimed to bring to the fore multifarious aspects of motilin research with a view to aiding prioritization of future studies on this gastrointestinal peptide.

Expert opinion: Growing evidence indicates that rodents (mice, rats, guinea pigs) do not have functional motilin system and, hence, studies in these species are likely to have a minimal translational impact. Both the active peptide and motilin receptor were initially localized to the upper gastrointestinal tract only but more recently – also to the brain (in both humans and other mammals with functional motilin system). Motilin is now indisputably implicated in interdigestive contractile activity of the gastrointestinal tract (in particular, gastric phase III of the migrating motor complex). Beyond this role, evidence is building that there is a cross-talk between motilin system and the brain-pancreas axis, suggesting that motilin exerts not only contractile but also orexigenic and insulin secretagogue actions.

KEYWORDS:

• Motilin
• gastrointestinal motility
• metabolism
• brain
• pancreas

Article highlights

• Motilin is involved in mediating phase III of the migrating motor complex in the interdigestive state.

• Emerging evidence suggests the role of motilin in the regulation of hunger and food intake.

• There is a cross-talk between motilin and pancreatic hormones (in particular, insulin and pancreatic polypeptide), with the potential to modulate blood glucose homeostasis.

Declaration of interest

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or conflict with the subject matter or materials discussed in this manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This study was part of the COSMOS program. COSMOS is supported, in part, by the Royal Society of New Zealand (Rutherford Discovery Fellowship to Associate Professor Max Petrov), which played no role in the study design; collection, analysis, interpretation of data; or writing of the manuscript.