The role of endogenous prostaglandins in maintaining the integrity of the gastric mucosa in Shay's ulcer model after truncal vagotomy in rat.

: The changes in the difference in the transmucosal potential of the stomach, in the ion flux of the mucosa and the prostaglandin content of the mucosa were studied after pyloric ligation combined with truncal vagotomy in rats. Results indicate that 10 hours following insertion of the pyloric ligation, and still prior to appearance of macroscopic ulceration, the mucosal barrier is damaged indicated by the decrease in PD value and by a changed ion flux. The development of these changes is prevented by truncal vagotomy performed simultaneously with pyloric ligation. Following pyloric ligation, simultaneously with the damage of the mucosal barrier, the PGF2 alpha concentration of the antrum and the rumen decreased. The 6-keto-PGF1 alpha content remained unchanged, while TXB2 content of the rumen increased. After truncal vagotomy the 6-keto-PGF1 alpha level of the antrum and the rumen and the TXB2 level of the rumen are increased. After truncal vagotomy performed simultaneously with pyloric ligation, the TXB2 content of the gastric mucosa increases with an increase also in the 6-keto-PGF1 alpha level of the rumen and the antrum and one in the PGF1 alpha content of the antrum, too. It is assumed that the beneficial effect of truncal vagotomy on the mucosal barrier is due to factors which are the known (i) decrease in H-ion secretion (ii) the unchanged bicarbonate secretion and (iii) the influencing of the prostaglandin level of the mucosa.