THE EFFECT OF SECRETIN ON THE CYSTEAMINE INDUCED INHIBITION OF ALKALINE SECRETION BY THE DUODENAL MUCOSA

To investigate the significance of neutralization of acid in the duodenaum, the proximal duodenal loop of rats, excluding the bile duct opening, was perfused with acidic saline, and the amount of alkali secreted by the loop was determined by continuous titration using pH-stat. The influence of cysteamine and secretin on the alkaline secretion was studied. It was found that the proximal duodenal mucosa of rats secretes bicarbonate enough to neutralize the incoming acid. A significant inhibition of the alkaline secretion by cysteamine, in a dose enough to induce perforating duodenal ulcers, and a significant reversal of the cysteamine-induced inhibition of the alkaline secretion were also found. From the above findings, the possible participation of the impaired alkaline secretion to the formation of duodenal ulcers and the therapeutic role of secretin to improve the alkaline secretion were indicated.