Effect of adding albumin to solutions of cholecystokinin on pancreatic protein output and pancreatic polypeptide release.

In four conscious dogs with chronic gastric and pancreatic Thomas fistulas we studied the effect of 99% pure cholecystokinin-33 (CCK-33) solutions on pancreatic secretion and PP release. CCK-33 was dissolved in 0.154 M NaCl alone or in the same solution containing 1 g per 100 ml dog albumin. The response of pancreatic protein output to increasing doses of CCK-33 (0.5, 1, 2, 4 IDU/kg per h) was significantly (P less than 0.05) higher when CCK was dissolved in NaCl with albumin than in NaCl alone. These results were confirmed by measuring CCK immunoreactivity in samples from tips of infusion lines by a gastrin radioimmunoassay. Release of pancreatic polypeptide (PP) following increasing doses of CCK-33 was also significantly (P less than 0.05) elevated when CCK was dissolved in an albumin-containing solution. There was a significant (P less than 0.02) correlation between plasma concentrations of PP and pancreatic protein output. This study suggests that albumin should be added to CCK-33 solutions to preserve biological activity. The biological effect of CCK-33 may be substantially underestimated if albumin is omitted.