The mammalian pancreas is a mixed exocrine and endocrine gland that produces digestive enzymes and hormones. The enzymes are stored and released by cells of the exocrine portion. The hormones are synthesized by cells that are clustered in the islets of Langerhans. The pancreas develops from fusion of a dorsal and ventral primordia which appear as buds from the embryonic It is generally believed that, in embryos, the pancreatic duct contains undifferentiated precursor cells that migrate away from the duct to generate both islet and acinar cells. Endocrine cell differentiation begins while the pancreatic cell precursors are still within the pancreatic duct?” Increase in islet cell number during embryonic development and early postnatal life occurs by neogenesis of islet cells from the pancreatic duct and by cell division of differentiated islet cell^.^,^,^ In mice, islets achieve a typical mature configuration after birth. Insulin (IN)-containing@-cells form the core of the islets and the other three classical endocrine cell types, the a-, 6-and PP-cells, which synthesize glucagon (GLU), somatostatin (SOM) and pancreatic polypeptide (PP) respectively, are located in the periphery of the islet.