Background and aim: Glucagon-like peptide-2 (GLP-2) and peptide YY (PYY) are produced in endocrine L-cells of the intestine and secreted in response to food intake. GLP-2 has a trophic effect on the intestinal epithelium, whereas PYY has pro-absorptive effects. It can be speculated that, in inflammatory bowel disease (IBD), the production and secretion of GLP-2 and PYY could be affected as a part of a regulatory mechanism. Therefore, tissue levels and meal-stimulated secretion of GLP-2 and PYY were studied in IBD patients and compared to controls.
Methods: Outpatients with IBD and control patients were included. Mucosal biopsies were taken from the ileum and colon and the content of GLP-2 and PYY was measured. After colonoscopy the patients took a mixed meal and plasma was collected for 90 min for plasma measurements of GLP-2 and PYY.
Results: Tissue levels of GLP-2 in control patients were highest in the terminal ileum (407+/-82 pmol/g tissue, n=10), whereas PYY was highest in the rectum (919+/-249 pmol/g tissue, n=10). In IBD patients with acute inflammation, the content of GLP-2 was similar to controls, whereas PYY was decreased to 72.1+/-17.7% (P=0.03, n=13) of control values. Neither the fasting plasma levels nor the meal responses of GLP-2 and PYY differed between controls and IBD patients.
Conclusion: The similar responses of GLP-2 and PYY in patients and controls do not support the suggestion that L-cell secretion is altered in IBD. The decreased tissue PYY concentrations may contribute to the diarrhoea of some of these patients.