Abstract
After the gut endoderm is formed, subsequent permissive induction signals from notochord allows the pancreas to merge and outgrows from the specific site of the embryonic gut epithelium. The first pancreas specific gene, pdx-1, is expressed around this stage. Interaction between pancreatic epithelium and surrounding mesenchyme allows the pancreas bud to further grow and differentiate to form ductal, exocrine or endocrine lineages. Several lines of evidence from gene knockout mouse and cell lineage studies suggest that a common pancreas stem cell first give rise to exocrine and endocrine progenitor cells. The endocrine progenitor then give rise to four different endocrine cells, α, β, δ, and PP cells, although it is not known how and when these cells arise. However, knowledge on the molecular mechanism how the genes define the pancreatic cell lineage is very limited. To date, pancreas remains to be one of the least understood organ in terms of the molecular mechanism of development. Identification of essential genes that regulate pancreas differentiation is indispensable for lineage specific differentiation of stem cells in culture. Here, I reviewed the literatures on development and regeneration of the Pancreas. Some recent results on growing pancreatic beta cells from ES (embryonic stem) cells are also introduced.
