Pax 4 and 6 regulate gastrointestinal endocrine cell development

The mechanisms behind the cell-specific and compartmentalized expression of gut and pancreatic hormones is largely unknown. We hereby report that dele tion of the Pax 4 gene virtually eliminates duodenal and jejunal hormone-se creting cells, as well as serotonin and somatostatin cells of the distal st omach, while deletion of the Pax 6 gene eliminates duodenal GIP cells as we ll as gastrin and somatostatin cells of the distal stomach. Thus, together, these two genes regulate the differentiation of all proximal gastrointesti nal endocrine cells and reflect common pathways for pancreatic and gastroin testinal endocrine cell differentiation. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.