Role of Cholecystokinin in the Regulation of the Interdigestive Phase of Pancreatic Secretion

Abstract

The rate of pancreatic secretion during the interdigestive state varies with the phase of interdigestive motility. During phases II and III of interdigestive motility, pancreatic secretion is greatest, and minimal during phases I and IV. Pancreatic polypeptide and motilin have been reported to be increased during phases II and III but do not appear to be responsible for the stimulation of pancreatic secretion. We have investigated the role of cholecystokinin (CCK) in regulating pancreatic secretion during the interdigestive state. Eight volunteers underwent a study of interdigestive duodenal motility with a catheter that collected pancreatic secretions at the ligament of Treitz. The phase of motility was correlated with the output of trypsin and the plasma CCK levels. The output of trypsin during phases II and III was 0.9 +/- 0.2 and 1.0 +/- 0.2 mg/kg/h, respectively, and decreased to 0.3 +/- 0.1 mg/kg/h during phase IV-I (p less than 0.05). To determine if the output of trypsin during phases II and III was responsible for the increases in plasma CCK, the effect of intraduodenal trypsin, 3 mg/kg/h, in five volunteers was determined. The infusion significantly increased the output of trypsin to a mean of 3.1 +/- 1.9 mg/kg/h (p less than 0.05). The plasma CCK concentration increased with intraduodenal trypsin from 20.4 +/- 5 to 26.4 +/- 3.7 pg/ml (p less than 0.05). The infusion study was repeated in two volunteers with heat-inactivated trypsin. The mean CCK level rose from 19.6 +/- 4 to 23.8 pg/ml.(ABSTRACT TRUNCATED AT 250 WORDS)