The pancreas plays a central role in digestion and absorption as well as utilization and storage of energy substrates. As described in Chapter 1, it consists of two structurally distinct but functionally integrated glandular systems, namely the exocrine and endocrine pancreas, both of which arise from an outgrowth of the primitive gut. Secretion by the exocrine pancreas is modulated by neural and hormonal signals, particularly in the form of numerous gastrointestinal peptide hormones (Chey & Chang, 2001). Due to the lack of basal membranes or compartmentalization capsules for different cell types in the pancreas, the islets cells are interspersed within the exocrine acini. Acini located near islets, called peri-insular acini, are composed of larger sized cells possessing larger nuclei and more abundant zymogen granules than acini removed from islets, called tele-insular acini. Some secretory products of the islet cells, such as insulin, interact directly with acinar cells and thereby regulate acinar function (Murakami et al., 1992). The exclusive morphology of the peri-insular acini is reflected in the presence of high insulin concentrations in the region (von Schonfeld et al., 1994).