Effects of GLP-1 and Other Gut Hormone Receptors on the Gastrointestinal Tract and Implications in Clinical Practice

Agonists targeting the receptors of incretin hormones, glucagon-like peptide-1 and glucose-dependent insulinotropic peptide, have been well established for the treatment of type 2 diabetes mellitus. There is increasing awareness that gastroenterologists and hepatologists should be treating obesity when patients present to their clinics. In addition, gastroenterologists and hepatologists should be aware of the effects of these classes of medications prescribed by other providers. Therefore, given the widespread use of incretin agonists for obesity treatment and weight loss, it is important to recognize their effects in the gastrointestinal tract, which could constitute significant benefits in weight loss and cardiometabolic benefits, but can be associated with adverse effects that constitute a potential barrier to their use, particularly at higher doses. Multiple studies reviewed in this article document the diverse effects of these drugs on the glucagon-like peptide-1 receptors that are widely expressed in the human body, including the nervous system modulating appetite, the gastrointestinal tract modifying gastric emptying, and lipid metabolism regulation leading to reduction in fat deposition. The objective of this review is to summarize the mechanism of action of incretin receptor agonists, their effects in the gastrointestinal tract, and implications in clinical practice, particularly in the practice of gastroenterology, endoscopy, and surgery.