[Cross-talk among pancreatic alpha, beta and delta cells stimulated by incretin hormones].

Incretin hormones, GLP-1 and GIP, contribute to whole body glucose homeostasis by modulating secretion of islet hormones, insulin, glucagon and somatostatin. Both GLP-1 and GIP stimulate insulin and somatostatin secretion. While glucagon secretion is stimulated by GIP, GLP-1 suppresses glucagon secretion. The mechanism by which GLP-1 suppresses glucagon secretion seems to include direct action of the hormone on alpha cells and indirect one through activation of beta and delta cells. However, molecular details of these actions still remain elusive.