Effect of various concentrations of calcium on arginine-induced insulin and glucagon release in vitro.

The effect of extracellular calcium concentration on the insulin and glucagon release in response to arginine from the isolated perfused rat pancreas, has been studied. All the experiments were carried out in the absence of glucose in the perfusate. Arginine 10 mM elicited a biphasic glucagon release, and a monophasic insulin response. In the presence of calcium 2.5 mM an increase of total insulin and glucagon in response to arginine were obtained. The increase in glucagon release was only detectable during the second phase, while first phase was not modified by the concentration of calcium present in the perfusate. The results of this study show that extracellular calcium concentration influences positively insulin and glucagon responses to arginine in vitro.