How The Islet Cell Works

Diagram of sequence resulting in insulin secretion from the pancreatic beta cell

The K-ATP channel comprises two subunits:

Note that closure of the K-ATP channel by sulphonylureas or glucose sensing causes the depolarization that triggers insulin release. Diazoxide is a K-ATP channel opener.

The effects shown are amplified by other mechanisms not shown, including incretin effects of GLP-1. The presence of additional mechanisms explains why glucose-dependent insulin secretion persists despite high-dose SU treatment.