Effect of cholecystokinin variant (CCK39) on dispersed acinar cells from guinea pig pancreas.

In dispersed acinar cells from guinea pig pancreas, cholecystokinin variants (CCK39 and CCK33) or carboxyl-terminal octapeptide of cholecystokinin (CCK-OP) caused significant increases in outflux of 45Ca, cyclic GMP, and release of amylase. In homogenates of acinar cells each peptide caused a significant increase in adenylate cyclase activity. For each function tested (1) CCK39 was equipotent with with CCK33, (2) CCK39 and CCK33 were 10 to 30 times less potent than CCK-OP, (3) the efficacies of CCK39, CCK33, and CCK-OP were the same, and (4) none of these effects were altered by concentrations of atropine sufficient to abolish the action of muscarinic cholinergic agents.