The role of calcium ions in the process by which nutrients affect glucagon secretion by pancreatic islet α-cells remains the matter of an apparently endless debate. In the prolongation of recent articles dealing with...The role of calcium ions in the process by which nutrients affect glucagon secretion by pancreatic islet α-cells remains the matter of an apparently endless debate. In the prolongation of recent articles dealing with this matter, the present review draws attention to the dual role of Ca2+ as revealed by prior publications. In such a perspective, emphasis is placed on the increase in glucagon output in response to the omission of extracellular Ca2+ as recorded in the presence of D-glucose or 2-ketoisocaproate, the permissive role of extracellular Ca2+ in the positive secretory response to arginine or a mixture of fumarate, glutamate and pyruvate, and the effects of an organic calcium-antagonist on glucagon output. Considering the role currently ascribed to Ca2+ in the activation of motile events involved in stimulus-secretion coupling, attention is also given to the effects of cytochalasin B, D2O and mitotic-spindle inhibitors upon the secretory response of α-cells exposed to D-glucose in the absence or presence of arginine.展开更多
文摘The role of calcium ions in the process by which nutrients affect glucagon secretion by pancreatic islet α-cells remains the matter of an apparently endless debate. In the prolongation of recent articles dealing with this matter, the present review draws attention to the dual role of Ca2+ as revealed by prior publications. In such a perspective, emphasis is placed on the increase in glucagon output in response to the omission of extracellular Ca2+ as recorded in the presence of D-glucose or 2-ketoisocaproate, the permissive role of extracellular Ca2+ in the positive secretory response to arginine or a mixture of fumarate, glutamate and pyruvate, and the effects of an organic calcium-antagonist on glucagon output. Considering the role currently ascribed to Ca2+ in the activation of motile events involved in stimulus-secretion coupling, attention is also given to the effects of cytochalasin B, D2O and mitotic-spindle inhibitors upon the secretory response of α-cells exposed to D-glucose in the absence or presence of arginine.
