“After the combination of either phenylalanine or tryptophan with pentagastrin , the H2-receptor antagonist significantly inhibited gastric acid secretion, whereas somatostatin, atropine, and the prostaglandin E1 analogue were not effective.”
“ Phenylalanine and tryptophan potentiated the gastric secretory responses following low doses of pentagastrin , whereas their effects on acid secretion stimulated by low doses of histamine or the cholinergic bethanecol were additive.”
“These results indicate that both phenylalanine and tryptophan potentiate gastric acid secretion stimulated by a submaximal dose of pentagastrin , whereas their effects on histamine- and bethanecol-stimulated secretion are additive.”