Islet cell neogenesis in the pancreas.

The beta cell population of the endocrine pancreas may expand by either of two processes, neogenesis or replication. While replication requires the existence of an already differentiated beta cell, neogenesis depends on the presence of active stem cells. Since the replicative activity of highly specialized cells such as beta cells seems to be limited, it is interesting to study the potential of the endocrine pancreas for beta cell neogenesis. In this article we review both the current state of knowledge of beta cell neogenesis under natural conditions and in response to stimulation, and the significance of neogenesis for beta cell growth in health and disease.