Proliferative activity of gastric and duodenal endocrine cells in the rat

The replicative activity and migration of gastrin, somatostatin and serotonin cells in rat stomach and duodenum was studied using combined immunocytochemistry and autoradiography after 3H thymidine pulse-labeling. Our results show that a small proportion of gastrin, somatostatin and serotonin immunoreactive cells displays proliferative activity. The overall labeling index ranged from 1.3% for gastric endocrine cells to 3.2% for duodenal endocrine cells. In a pulse chase experiment, labeling indices of immunoreactive cells were estimated at several time intervals after 3H thymidine administration. Significant differences in labeling index were not found. Migration of 3H thymidine labeled endocrine cells towards the luminal surface was not found in the stomach nor in the duodenum. It is concluded that 1) these endocrine cells have replicating activity; 2) the replicative activity of endocrine cells is higher in the duodenum than in the stomach; 3) the various cell types do not show significant differences in replicating activity and 4) endocrine cells did not seem to migrate to the luminal surface of the mucosa along with the other epithelial cells.