What is the mechanism of action of sulphonylureas in the context of insulin secretion?

Sulphonylureas function primarily by enhancing insulin secretion from the pancreas. They achieve this by binding to specific receptors on pancreatic beta cells, known as sulphonylurea receptors, which are a part of the ATP-sensitive potassium channels. When these receptors are activated, they lead to the closure of potassium channels, resulting in cell depolarization. This depolarization opens voltage-gated calcium channels, allowing calcium ions to enter the cell. The influx of calcium triggers the release of stored insulin into the bloodstream, effectively increasing insulin levels in response to blood glucose levels.

This mechanism makes sulphonylureas effective in managing blood sugar levels, particularly in type 2 diabetes patients who have functional beta cells but cannot produce sufficient insulin on their own. The ability to stimulate insulin secretion means that, in the context of managing hyperglycemia, sulphonylureas can significantly improve glycemic control.