HYPERGASTRINEMIA INCREASES PROLIFERATION OF GASTRODUODENAL EPITHELIUMDURING GASTRIC-ULCER HEALING IN RATS

We investigated if hypergastrinemia exerted any influence on the proli feration of gastroduodenal epithelium during the healing of ulcers in rats. A mucosal ulcer was induced in the corpus region of the stomach in three groups of rats, which were then given vehicle, omeprazole (40 0 mu mol/kg/day), or gastrin-17 (60 nmol/kg/day) for three or six days . A fourth group of unoperated rats served as controls, One hour befor e killing, [H-3]thymidine was injected. The ulcer margin and correspon ding control tissues were excised and processed for light microscopic determination of epithelial labeling index (LI), mitotic index, and ap optotic index. LI was also determined in other parts of the gastroduod enal mucosa, Three and six days after the ulcer operation, the LI in t he vehicle-treated ulcer rats was significantly increased in the ulcer margin and in the duodenum, in comparison with the intact controls, I n the ulcer margin, the mitotic index was significantly increased, in parallel with the LI; the apoptotic index remained at the control leve l, The LI in the ulcer margin was increased further after administrati on of omeprazole or gastrin-17, which elevated the plasma gastrin leve ls by 5-15 times, It is concluded that hypergastrinemia may increase c ell proliferation in the ulcer margin, which may accelerate the rate o f healing.