What is the mechanism of GLP-1 receptor agonists?

• A. Slows gastric emptying, glucose-dependent insulin release, inhibits glucagon release, suppresses appetite
• B. Directly stimulates insulin release irrespective of glucose
• C. Blocks glucose reabsorption in kidney
• D. Inhibits hepatic glucose production

Answer: (A)

GLP-1 receptor agonists mimic the natural incretin GLP-1, coordinating postmeal glucose control by four main actions: they stimulate insulin release from pancreatic beta cells in a glucose-dependent manner, they suppress glucagon secretion from alpha cells (reducing hepatic glucose output after meals), they slow gastric emptying to blunt the rise of blood glucose after eating, and they act in the brain to suppress appetite. The glucose-dependent insulin response means the drug raises insulin when glucose is high but has limited effect when glucose is normal, helping to reduce the risk of hypoglycemia when used alone. This combination of effects is why the mechanism described—slowing gastric emptying, glucose-dependent insulin release, inhibiting glucagon, and suppressing appetite—best fits GLP-1 receptor agonists. The other options describe actions typical of different drug classes: insulin release irrespective of glucose (sulfonylureas), blocking glucose reabsorption in the kidney (SGLT2 inhibitors), or inhibiting hepatic glucose production (metformin).