Direct measurement of pancreatic enzymes after stimulation with secretin versus secretin plus cholecystokinin

Background: Direct measurement of pancreatic enzymes after administration o f pancreatic secretagogues is the gold standard in the assessment of exocri ne pancreatic function. Recent experience at the authors' institution showe d that endoscopic collection of pancreatic secretions 5, 10, and 15 minutes after intravenous administration of secretin is useful in screening for pa ncreatic insufficiency. Concomitant administration of intravenous cholecyst okinin has been a subject of debate. The pur pose of this study was to comp are pancreatic enzyme levels after administration of secretin versus secret in plus cholecystokinin and to validate the timing of collection of duodena l fluid. Methods: A prospective, randomized, double-blind study was conducted from S eptember 1997 through September 1998. Patients scheduled for pancreatic enz yme sampling were randomly assigned to receive intravenous secretin (2 U/kg ) plus placebo (goup 1) or intravenous secretin (2 U/kg) plus cholecystokin in (0.02 mu g/kg [Group 2]). Duodenal fluid was collected 5, 10, and 15 min utes later and placed in dry ice. Samples were measured for the levels of t rypsin, amylase, lipase, and chymotrypsin. Results: Twenty patients were assigned to each group. The age range was sim ilar in both groups: 12 months to 16 years, 8 months in group 1 (median, 2. 1 years) and 15 months to 13 years, 7 months in group 2 (median, 2.5 years) . Group 2 had a greater number of patients with all four enzymes at normal levels during at least one of the time points, 75% versus 50% (P = 0.102). The difference in enzyme levels at the 5-, 10-, and 15-minute collections w as statistically significant. For all four enzymes in both groups, values v aried from highest to lowest with time (P = 0.0001). The enzyme levels at 1 0 minutes were close to the enzyme levels at 5 minutes; the lowest values o ccurred at 15 minutes. Conclusions: Higher pancreatic enzyme levels were obtained after administra tion of secretin plus cholecystokinin, although the trend did not reach sta tistical significance. Pancreatic enzyme levels are highest at 5 and 10 min utes, indicating that collections of duodenal fluid should be completed wit hin 10 minutes of the administration of the secretagogues.