Evaluation of biologic gastrin activity of compound CI-988 in the isolated, vascularly perfused rat stomach

BACKGROUND: The peptoid CI-988 has previously been shown to have high affinity for the cholecystokinin (CCK)-B/gastrin receptor and has been reported to be a powerful CCK antagonist in many systems, although it has agonist activity on histidine decarboxylase in the rat. METHODS: In the present study the effect of CI-988 on acid secretion and histamine release in the totally isolated, vascularly perfused rat stomach was assessed. RESULTS: CI-988 was found to be a gastrin agonist with regard to the stimulation of both histamine release and acid secretion. CONCLUSION: Thus, in this stomach model CI-988 behaved as a CCKB/gastrin agonist. The present study underlines the importance of testing the biologic activity of ligands in models with sufficient sensitivity.