Relative bioactivities of cholecystokinins-8 and -33 on rat pancreatic acini.
The relative potencies of cholecystokinin (CCK-33) and its carboxyl terminal octapeptide (CCK-8) for stimulation of amylase release from rat pancreatic acini was measured. Porcine CCK-33 and synthetic CCK-8 were initially subjected to high pressure liquid chromatography to assess purity. Concentrations of each peptide were determined by amino acid analysis. The relative immunoreactivities of CCK-33 and CCK-8 were compared using an antibody that recognizes the common carboxyl terminus of these forms. This antibody bound CCK-8 and CCK-33 with nearly equal affinity. The relative potencies of CCK-33 and CCK-8 were then measured by comparing their abilities to stimulate amylase release from isolated rat pancreatic acini. Statistical analysis of the relative potencies of the two hormones indicated that CCK-8 was 36% more potent than CCK-33 in this assay system. These data suggest that differences in biological activities between large and small forms of CCK are not as great as previously reported.
D000596:Amino Acids / Q000032:analysis; D000681:Amylases / Q000378:metabolism*; D000818:Animals; D002766:Cholecystokinin / Q000494:pharmacology*; D010179:Pancreas / Q000201:enzymology*; D010189:Pancreatic Juice / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D012844:Sincalide / Q000494:pharmacology*
D000596:Amino Acids; D002766:Cholecystokinin; D000681:Amylases; D012844:Sincalide