A study on gastric ulcers induced by long-term fasting in rats

The present study was performed to investigate the roles of intragastric pH and PAS positive mucus as to the incidence of gastric ulcers after long-term fasting in rats. Gastric ulcers in the forestomach and corpus were found at 4 and 6 days after fasting, respectively. The intragastric pH was significantly reduced at 1, 2, 3, 4, 6 and 7 days after fasting, but tended to have returned to control levels at 8 days. PAS positive mucus was significantly increased at 2 to 7 days, but there was no significant change at 8 days. From these results, it seems that the aggressive factor is not involved, but attenuation of the defensive factor is important as to the incidence of this type of ulcer. As one of the causes of this attenuation, a decrease in the gastric mucus volume was suggested.