K-ATP-channels and glucose-regulated glucagon secretion

Glucagon, secreted by the a-cells of the pancreatic islets, is the most important glucose-increasing hormone of the body. The precise regulation of glucagon release remains incompletely defined but has been proposed to involve release of inhibitory factors from neighbouring P-cells (paracrine control). However, the observation that glucose can regulate glucagon secretion under conditions when insulin secretion does not occur argues that the a-cell is also equipped with its own intrinsic (exerted within the a-cell itself) glucose sensing. Here we consider the possible mechanisms involved with a focus on ATP-regulated K+-channels and changes in a-cell membrane potential.