Commentaries

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 modula-tion of insulin secretion is of great interest to diabetolo-gists. 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 diVerent in the pancreas and intestine. In the pancreas it is cleaved to produce glucagon