Glucose action 'beyond ionic events' in the pancreatic beta cell

For normal glucose homeostasis, insulin release by the pancreatic beta cell is vital. Until recently, it was thought that glucose-induced ionic events , such as closure of the ATP-sensitive K+ (K-ATP) channels, membrane depola rization, activation of the L-type voltage-dependent Ca2+ channels, Ca2+ in flux and elevation of cytosolic free Ca2+, constitute the main signalling p athway in beta-cell stimulus-secretion coupling. However, since the disc ev ery of 'non-ionic' glucose actions in the beta cell by the Aizawa and Henqu in laboratories in 1991, data have accumulated th at strongly indicate the physiological relevance of this signalling pathway. In this review, Torn Ai zawa and colleagues discuss how the K-ATP channel-Ca2+ hypothesis was formu lated, what was overlooked in the hypothesis, and then provide a comprehens ive view of stimulus-secretion coupling in the beta cell, with an emphasis on non-ionic glucose actions.