The stomach contains GLP-1-producing cells that contribute to circulating levels of GLP-1, a marker of improved glucose homeostasis in obese subject having undergone a bariatric surgery
Glucagon-Like Peptide-1 (GLP-1) is a proglucagon derived peptide, mainly produced by endocrine L cells in the ileum and colon, that exerts biological effects on pancreas, stomach, liver, brain and heart. GLP-1 is involved in the regulation of postprandial glycaemia by increasing insulin secretion and slowing gastric emptying through activation of specific GLP-1 receptors. In obese subjects, GLP-1 secretion is impaired but its restoration after bariatric surgery could contribute to the improvement of blood glucose control.
In their published article in Nature communications (January 4, 2021), the PIMS’ research team (head: M. Le Gall & A Bado) demonstrates the presence of GLP-1 expressing cells in the rat and human stomach. Intragastric administration of glucose in the rat in vivo rapidly increases circulating levels of total and active GLP-1 in both the gastric and the portal veins, suggesting the contribution of gastric GLP-1 to levels of GLP-1 in the portal vein and the general circulation. The elevation of GLP-1 in the portal vein is impaired in HFD obese rats but restored after sleeve gastrectomy, a recovery probably contributing to the beneficial metabolic effects of bariatric surgery.
Moreover, these gastric GLP-1-expressing cells, whose number and secretion capacity increase in obese subjects operated on bariatric surgery, may locally modulate gastric functions to control glucose homeostasis. This local action could be exerted through activation of GLP-1 receptors in the pyloric muscle and vagal nerve, resulting in reduced gastric emptying, one of the mechanisms of action of anti-diabetic drugs. Finally, these data, highlighting the potential role of stomach produced active GLP-1, question its role in physiology and metabolism.