Mechanism of action of exenatide in diabetes mellitus is
**Core Concept**
Exenatide is a glucagon-like peptide-1 (GLP-1) receptor agonist used in the management of type 2 diabetes mellitus. GLP-1 receptor agonists mimic the action of the incretin hormone GLP-1, which enhances glucose-dependent insulin secretion and suppresses glucagon release.
**Why the Correct Answer is Right**
Exenatide binds to and activates the GLP-1 receptor on pancreatic beta cells, stimulating insulin secretion in a glucose-dependent manner. This action increases insulin release in response to elevated blood glucose levels, thereby reducing hyperglycemia. Exenatide also delays gastric emptying, reduces postprandial glucagon levels, and has a mild weight-reducing effect.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the mechanism of action of exenatide.
* **Option B:** Exenatide does not work by inhibiting the enzyme dipeptidyl peptidase-4 (DPP-4), which is the mechanism of action of DPP-4 inhibitors like sitagliptin.
* **Option D:** Exenatide does not work by stimulating the release of insulin from pancreatic alpha cells.
**Clinical Pearl / High-Yield Fact**
GLP-1 receptor agonists like exenatide are associated with a reduced risk of major adverse cardiovascular events compared to sulfonylureas or insulin therapy in patients with type 2 diabetes mellitus.
**Correct Answer: C. Exenatide binds to and activates the GLP-1 receptor on pancreatic beta cells, stimulating insulin secretion in a glucose-dependent manner.**