Glucagon-like peptide 1 (GLP-1) is a peptide hormone found in the small intestine and colon which is released in response to luminal nutrients and which has now been found to exert a number of important functions on the gastrointestinal tract and pancreas.1 Its role in the modulation of insulin secretion is of great interest to diabetologists. Its functions on the upper gastrointestinal tract and potential roles in therapy of upper gut disorders are however less well known.

The mammalian glucagon precursor (pro-glucagon) is produced both in the alpha cells of the islets of Langerhans and in specialised enteroendocrine cells (L cells) of the intestinal and colonic mucosa.2 Processing of the pro-glucagon precursor is different in the pancreas and intestine. …