Colonic inhibition of gastric acid secretion in the dog

The colon has been shown to contain an abundance of endocrine cells. Their role is not yet understood. In four dogs prepared with chronic gastric fistula and colonic fistula in the cecum the effects on pentagastrin dose responses of colonic perfusion with the following substance were studied: saline, 15% liver extract pH 7.0; sodium oleate pH 9.4; and 0.08 M HCl. The responses obtained in each of the perfusion studies were compared with those obtained without colonic perfusion. Whereas saline had no effect on these responses, liver extract, sodium oleate, and HCl, each produced significant inhibition. These results suggest that the colon has the capacity for inhibiting gastric acid secretion by some mechanism which may prove to be humoral. Until now the colon has rarely been considered in any assessment of the gut functioning as an endocrine organ. Perhaps a colonic endocrine role should now be given further consideration.