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.