What is the mechanism of action of GLP-1 receptor agonists and their benefits in type 2 diabetes?

• A. Inhibit hepatic glucose production and increase insulin sensitivity.
• B. Enhance glucose-dependent insulin secretion, suppress glucagon, slow gastric emptying, and promote weight loss.
• C. Block renal glucose reabsorption.
• D. Directly increase pancreatic beta cell mass.

Answer: (B)

GLP-1 receptor agonists mimic the incretin hormone GLP-1 released after meals. They bind to GLP-1 receptors on pancreatic beta cells to boost insulin secretion in a glucose-dependent manner, so more insulin is released when blood glucose is high and less when glucose is normal, which helps reduce the risk of hypoglycemia. They also suppress glucagon release from alpha cells during hyperglycemia, lowering hepatic glucose production. In addition, they slow gastric emptying, blunting postprandial glucose rises, and act on the brain to promote satiety, which often leads to weight loss. Taken together, these effects improve glycemic control, reduce postprandial glucose, and can support weight management, with a relatively low risk of hypoglycemia when used alone or with agents that don’t cause hypoglycemia. They do not primarily inhibit hepatic glucose production like metformin, do not block renal glucose reabsorption like SGLT2 inhibitors, and do not directly increase pancreatic beta cell mass in humans.