Gastric acid, plasma gastrin, and somatostatin responses to feeding and exogenous gastrin alone and in combination in conscious cats.

Meat in the stomach or duodenum potentiates pentagastrin-induced acid secretion in cats, presumably by a humoral mechanism. In the present study on cats, a meat meal significantly augmented the maximal acid response from a Heidenhain pouch (HP) to pentagastrin or to human synthetic gastrin I by 31 and 30%, respectively. The maximal HP acid response to pentagastrin was augmented also by peptone instilled into the stomach through a gastric fistula. Intravenous infusion of amino acids stimulated acid secretion but did not augment the maximal acid response to pentagastrin. The plasma concentrations of gastrin and somatostatin increased during infusion of pentagastrin and gastrin I and were not further altered by simultaneous feeding. The present results indicate that the mechanism for potentiation of gastrin-induced acid secretion is of physiological significance, since feeding augmented also the acid response to heptadecapeptide gastrin, the only gastrin secreted from the antrum and duodenum in cats. The potentiation of acid secretion is not dependent on the vagal excitation induced by oral feeding, since potentiation was demonstrated also by intragastric peptone instillation. The mechanism for the potentiation is not due to absorbed amino acids or a decrease of plasma somatostatin.