Hyperstimulation pancreatitis in mice induced by cholecystokinin octapeptide, caerulein, and novel analogues: effect of molecular structure on potency.

Acute pancreatic oedema with hyperamylasaemia was induced in mice by subcutaneous administration of cholecystokinin octapeptide (CCK8). Comparison with effect of caerulein showed that cholecystokinin is less potent in vivo. To investigate the observed difference in response, threonine3 CCK8 and methionine5 caerulein were synthesised and evaluated. Comparison of these peptides suggests that difference in bioactivity is related to possession of extra N-terminal residues rather than substitution of threonine for methionine.