Electrolyte composition of endoscopically collected duodenal drainage fluid after synthetic porcine secretin stimulation in healthy subjects

Background: Traditional pancreatic function tests are sensitive for the diagnosis of pancreatic exocrine insufficiency but are cumbersome and difficult to perform. A sedationless endoscopic pancreatic function test that has the potential for wide clinical application was developed by us, but data on the results of this method in healthy subjects are lacking. This study analyzed endoscopically collected duodenal fluid from healthy subjects after synthetic porcine secretin stimulation. Methods: Healthy subjects underwent the sedationless endoscopic pancreatic function test. After secretin stimulation, duodenal aspirates were obtained every 5 minutes for 1 hour. The collected fluid was analyzed for electrolyte concentrations. Results: Sixteen healthy subjects (8 women, 8 men; median age 34.5 years) underwent the endoscopic pancreatic function test. The concentrations of the sodium ([Na+]) and potassium ([K+]) cations remained constant, similar to normal concentrations in plasma (median [Na+], 155 mEq/L; median [K+], 4.3 mEq/L). The concentrations of the bicarbonate ([HCO3-]) and chloride anions increased and decreased, respectively, in an inverse and reciprocal manner, similar to the previously characterized "secretory curve." The median peak [HCO3-] was 108 mEq/L IQR: 99-110). By the 20-minute collection, the [HCO3-] was greater than 80 mEq/L for 94% (15/16) of subjects, the historic cut point for [HCO3-] in studies based on traditional methods of pancreatic function testing. Conclusions: Endoscopic collection of pancreatic fluid reproduces the anion-cation secretory curve described by prior studies of pancreatic secretory physiology based on traditional collection methods.