Biological activity of the C-terminal octapeptide of cholecystokinin, of three of its analogues and of caerulein in the dog.

Dose-response curves of the C-terminal octapeptide (CCK-8) of cholecystokinin, of 3 of its methoxinine analogues, and of caerulein for various variables of exocrine pancreatic secretion have been established in conscious dogs. The following relative potencies were calculated for the protein secretion activity of CCK-8 (100%), [Mox3]-CCK-8 (52%), [Mox6]-CCK-8 (27%), [Mox3,Mox6]-CCK-8 (19%) and caerulein (178%).