Effect of enprostil on amphibian gastroduodenal and human gastric bicarbonate secretion

The protective and ulcer healing properties of prostaglandins are well established. We have explored the possible mode of action of enprostil, a synthetic dehydroprostaglandin E2, on amphibian gastroduodenal mucosal bicarbonate secretion in vitro and on human gastric bicarbonate secretion in vivo. Addition of enprostil (10(-6) M) to the luminal solution of isolated amphibian gastric mucosa produced a 28% increase in bicarbonate secretion without a change in transmucosal potential difference. The same concentration of enprostil added to the luminal solution of isolated amphibian duodenal mucosa produced a 37% increase in bicarbonate secretion and was associated with a rise in transmucosal potential difference. The gastric output of bicarbonate from the human stomach has been calculated using a perfusion technique before, during, and after perfusion with enprostil (35 micrograms) in six healthy volunteers. A significant 78% increase in bicarbonate secretion occurred during the period of enprostil perfusion, falling to normal during the postenprostil period. These changes were caused mainly by an increase in gastric secretory volume with insignificant increases in bicarbonate concentration. These results suggest that stimulation of gastroduodenal bicarbonate secretion by enprostil may play a role in its protective actions.