Question

Which oral hypoglycemic agent increases the levels of incretin hormone by inhibiting the enzyme dipeptidyl peptidase-4 (DPP-4):

• A. Metformin
• B. Pioglitazone
• C. Sitagliptin
• D. Glipizide

Hint:

Sitagliptin is a DPP-4 inhibitor that boosts incretin levels, enhancing insulin secretion and improving glucose control in patients with type 2 diabetes.

Answer 1

The Correct Option is C

Sitagliptin is an oral hypoglycemic agent that works by inhibiting the enzyme dipeptidyl peptidase-4 (DPP-4). DPP-4 normally deactivates incretin hormones, which help to increase insulin secretion and decrease glucagon secretion in response to meals. By inhibiting DPP-4, Sitagliptin increases the levels of incretin hormones, improving blood sugar control.

Answer 2

The question is asking which oral hypoglycemic drug raises incretin hormone levels by blocking the enzyme dipeptidyl peptidase-4 (DPP-4). Let's look at each drug listed by its class and mechanism.

1. Metformin: This is a biguanide. It lowers blood sugar mainly by cutting down glucose production in the liver and improving how muscle and fat tissue respond to insulin. It has no effect on the DPP-4 enzyme or incretin hormones.
2. Pioglitazone: This belongs to the thiazolidinedione class. It works by activating PPAR-gamma receptors, which makes cells more sensitive to insulin. It does not act on DPP-4 or change incretin levels.
3. Sitagliptin: This drug belongs to the gliptin (DPP-4 inhibitor) class. Normally, the enzyme DPP-4 breaks down the incretin hormones GLP-1 and GIP within minutes of their release. By blocking DPP-4, sitagliptin lets these incretins stay active in the blood for longer, which boosts insulin release from the pancreas and lowers glucagon output from the liver.
4. Glipizide: This is a sulfonylurea. It stimulates insulin release directly by closing potassium channels on pancreatic beta cells. It does not touch the DPP-4 enzyme or incretin hormones.

Only sitagliptin acts on the DPP-4 enzyme pathway described in the question, since metformin, pioglitazone, and glipizide work through entirely separate mechanisms.

So the correct answer is Sitagliptin.