DURATION OF ANTI-CHOLECYSTOKININ (CCK) ACTION ON THE RAT EXOCRINE PANCREAS OF NEW CCK RECEPTOR ANTAGONIST FK480 ADMINISTERED ORALLY

We assessed the duration of the anti-cholecystokinin (CCK) action of F K480, a new non-peptide CCK-A receptor antagonist developed in Japan, in an in vivo study in rats, comparing it with CR 1505. Pancreatic exo crine secretion stimulated by intravenous infusion of CCK-8 (0.06 mu g /kg per h) was measured at intervals of 0-24 h after the oral administ ration of FK480 (1.5 mg/kg) and CR 1505 (30 mg/kg). FK480 significantl y inhibited both CCK-stimulated pancreatic juice volume flow and amyla se output 0, 4, 8, and 12 h after oral administration, whereas the inh ibitory effect of CR 1505 had completely disappeared by 8 h after oral administration. It was concluded that orally administered FK480 has a prolonged anti-CCK action.