Abstract
In cats with gastric fistulae and Heidenhain pouches, the effect of acid entering the duodenum on secretion of acid, pepsin and mucus from the Heidenhain pouch during maximal acid stimulation with pentagastrin or histamine, was studied. Duodenal acidification produced stimulation of pepsin and mucus secretion comparable to that induced by exogenous hormones (secretin and the combination of secretin with cholecystokinin). Duodenal acidification caused an increase in acid secretion, suggesting that, in addition to secretin and cholecystokinin, a factor that stimulates acid secretion was also released by acid.