Regulation of calcium in pancreatic α- and β-cells in health and disease

The glucoregulatory hormones insulin and glucagon are released from the beta- and a-cells of the pancreatic islets. In both cell types, secretion is secondary to firing of action potentials. Ca2+-influx via voltage-gated Ca2+-channels, elevation of [Ca2+](i) and initiation of Ca2+-dependent exocytosis. Here we discuss the mechanisms that underlie the reciprocal regulation of insulin and glucagon secretion by changes in plasma glucose, the roles played by different types of voltage-gated Ca2+-channel present in alpha- and beta-cells and the modulation of hormone secretion by Ca2+-dependent and -independent processes. We also consider how subtle changes in Ca2+-signalling may have profound impact on beta-cell performance and increase risk of developing type-2 diabetes. (C) 2011 Elsevier Ltd. All rights reserved.