Significance of insulin receptors in the action of sulphonylurea drugs.

The mechanisms by which sulphonylureas lower blood glucose are complex. Sulphonylureas increase insulin secretion and possibly also decrease glucagon release from the pancreas. In the periphery, they increase insulin binding to its receptors through direct or indirect mechanisms, primarily by increasing receptor number. Sulphonylureas also potentiate the action of insulin in peripheral glucose uptake and metabolism, even when no measurable effects on insulin receptors can be demonstrated. This post-receptor mode of action seems to play an important role in the spectrum of sulphonylurea effects.