Comparison of vasoactive intestinal peptide (VIP) and secretin in gastric secretion and mucosal blood flow

VIP and secretin were compared in regard to their effects on gastric acid and pepsin secretion induced by pentagastrin histamine or a peptone meal as well as on gastric mucosal blood flow and meal induced serum gastrin level in conscious dogs provided with gastric fistulas and denervated fundic pouches. Both VIP and secretin caused a dose-related stimulation of basal pepsin outputs and inhibition of pentagastrin-induced acid secretion. VIP, like secretin, inhibited pentagastrin and meal-induced gastric acid secretion but in contrast to secretin it caused inhibition of acid response to histamine. Inhibition of acid secretion by VIP or secretin was accompanied by secondary reduction in gastric mucosal blood flow in tests with pentagastrin or histamine and by depression of the serum gastrin level in tests with a peptone meal. This study indicates that in comparison with secretin, VIP has a wider spectrum of inhibition of stimulated gastric secretion and may be considered as one of the enterogastrones released in the small intestine.