Response to jejunal acidification in man. I. Changes in composition of perfusate.

The jejunal disposal of perfused acid was studied in 11 control subjects and 12 patients with duodenal ulcer. It was found that the capacity to dispose of acid was saturable and was less than control in patients with duodenal ulcer. When the load of acid was small, all the acid disappeared from the jejunum and sodium bicarbonate could be aspirated. During acid perfusion there was secretion of water and electrolytes into the jejunum if the load of acid exceeded the dissipative capacity. Superimposed intravenous infusion of secretin and cholecystokinin increased acid disposal, particularly in patients with duodenal ulcer, and increased the associated rate of secretion of water and electrolytes or changed net absorption to net secretion. We conclude, firstly, that acid is removed from the jejunum by secreted bicarbonate, and secondly that the whole of the upper small intestine of patients with duodenal ulcer is functionally abnormal.