Embryonic development of the endocrine pancreas

The majority of our current knowledge on human pancreas development has been deduced from data acquired from other species such as rodents. The endocrine portion of the pancreas consists of the islets of Langerhans which contain five hormone-producing cell types including the α-cells (glucagon), β-cells (insulin), δ-cells (somatostatin), PP cells (pancreatic polypeptide), and ε cells (ghrelin) the primary function of which is to regulate blood glucose levels in a dynamic manner. Numerous investigations have utilized the information obtained from developmental biology to serve as a model by which to direct the differentiation of stem cells into functional, hormone-producing pancreatic endocrine cells in vitro. In this chapter, we compare and contrast developmental similarities in both human and rodent pancreata. Special attention is paid to transcription factor cascades that lead to differentiation of insulin-producing β-cells and the spatiotemporal control of islet development.