Components of Mouse Pancreatic Islets and Are Differentially Expressed by Islet Endocrine Cell Types

The pancreatic islet is a complex mini-organ comprising numerous cell types. These include the well-recognized endocrine α, β, δ, and pancreatic polypeptide (PP) cell types, producing predominantly the hormones glucagon, insulin, somatostatin, and pancreatic polypeptide, respec-tively (Baetens et al. 1979; Halban 2004). The extensive intra-islet capillary network comprises endothelial cells, together with supporting pericytes and fibroblasts (Ballian and Brunicardi 2007; Olsson and Carlsson 2006). Sympa-thetic and parasympathetic fibers innervate the islet (Ahren 2000) and also require supporting cells such as Schwann cells (Smith 1975). The normal control of glucose metabo-lism requires exquisite integrated regulation of all of these cell types. To achieve this, communication between these cells i