Effect of low-dose exogenous secretin on pentagastrin- and meal-stimulated gastric acid secretion in humans.

Intravenous infusion of secretin in a dose of 0.05 CU/kg/hr inhibited pentagastrin-stimulated (100 ng/kg/hr) acid secretion by 42% (P less than 0.05) abd meal-stimulated (10% peptone, pH 5.5) acid secretion by 33% (P less than 0.05) in 10 healthy subjects. Median serum gastrin concentration during peptone stimulation was reduced by 24% (P less than 0.05) during secretin infusion. Median plasma secretin concentrations were 6.0 and 5.2 pmol/liter, respectively. Since these secretin concentrations are of the same magnitude as those seen after duodenal acidification, it is concluded that secretin may participate in the physiological inhibition of gastric acid secretion.