## **Core Concept**
Sulphonylureas are a class of medications used in the management of type 2 diabetes mellitus. They act by enhancing insulin secretion from the pancreatic beta cells. This mechanism is crucial for lowering blood glucose levels in patients with type 2 diabetes.

## **Why the Correct Answer is Right**
The correct answer, **D. Increasing insulin secretion**, is right because sulphonylureas work by binding to and closing ATP-sensitive potassium channels (K+ channels) in the pancreatic beta cells. This closure leads to cell depolarization, opening of voltage-gated calcium channels, and an influx of calcium ions. The increased intracellular calcium concentration triggers the exocytosis of insulin-containing granules, thereby increasing insulin secretion.

## **Why Each Wrong Option is Incorrect**
- **Option A: Decreasing glucose absorption** - This is incorrect because sulphonylureas do not primarily act by affecting glucose absorption from the gastrointestinal tract. Their main action is on insulin secretion.
- **Option B: Increasing insulin resistance** - This is incorrect because sulphonylureas actually decrease insulin resistance indirectly by enhancing insulin secretion, but their primary mechanism is not to directly affect insulin resistance.
- **Option C: Increasing gluconeogenesis** - This is incorrect because sulphonylureas do not act by increasing gluconeogenesis. In fact, enhanced insulin levels resulting from sulphonylurea use would decrease gluconeogenesis.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that sulphonylureas can cause hypoglycemia as a side effect due to their mechanism of increasing insulin secretion. This is a critical consideration, especially in elderly patients or those with renal impairment.

## **Correct Answer:** **D. Increasing insulin secretion**