Leucine and the intestinal phase of gastric acid secretion

The intestinal phase of gastric acid secretion is mediated by the putative hormone entero-oxyntin. The release of the hormone has been demonstrated in both dog and rat models during an intestinal meal of liver extract. The maximal gastric acid response to pentagastrin is augmented by the presence of liver extract in the intestine; this phenomenon serves as a bioassay for entero-oxyntin. We tested the hypothesis that one or more amino acids in liver extract causes the release and/or action of entero-oxyntin. Anesthetized rats, prepared with bilateral cervical vagotomies, received jejunal perfusion of mannitol (control), liver extract, or an amino acid. Intravenous pentagastrin was administered simultaneously at a dose known to produce maximal gastric acid output in rats. Our results show that of the amino acids tested, only leucine produced a significant augmentation of maximal pentagastrin-stimulated gastric acid secretion when compared with controls.