REG GENE-EXPRESSION IS INCREASED IN RAT GASTRIC ENTEROCHROMAFFIN-LIKECELLS FOLLOWING WATER IMMERSION STRESS

Background & Aims: Reg gene has been isolated from regenerating rat pa ncreatic islets, and subsequent studies have shown a trophic effect of Reg protein on islet cells. However, little is known about the role o f Reg protein in the stomach. The aim of this study was to clarify the localization of Reg messenger RNA (mRNA) and its product in the stoma ch and to examine changes in the level of their expression during rege neration of gastric mucosal cells. Methods: Gastric lesions were exper imentally induced in Sprague-Dawley rats by water immersion stress. No rthern blot analysis and in situ hybridization studies were performed to examine changes in mRNA levels. Immunohistochemical studies were pe rformed to identify the cellular localization and to investigate the c hange in Reg protein level. Results: Reg mRNA and its product were dis tributed in the basal part of the oxyntic mucosa and were expressed ma inly in enterochromaffin-like cells. Levels of both Reg mRNA and its p roduct were markedly increased in the water immersion-induced gastric lesions. Conclusions: Reg mRNA and its product are expressed in gastri c enterochromaffin-like cells, and their levels are increased during t he healing process of water immersion-induced gastric lesions.