The unstimulated pancreatic secretion obtained by endoscopic cannulation, and the plasma secretin levels in man.

The technique of collecting juice from the main pancreatic duct by siphonage is described. The juice was collected in 5-min fractions under basal conditions for 20 min (32 subjects) and extended to 60 min (6 subjects). Flow rate and bicarbonate concentration were significantly higher during the first collected samples, whereas concentrations of amylase and protein rose during the first 20 min of the study. All variables remained nearly constant after this period. Immunoreactive secretin (IRS) in peripheral plasma was significantly higher immediately after cannulation of the main pancreatic duct, as compared to the pre-endoscopic level. When the catheter was left in the duct and pancreatic juice drained, the IRS stabilized at a level not significantly different from the pre-endoscopic level. Positive correlations were found between flow rate and plasma level of IRS and between flow rate and bicarbonate concentrations. A negative correlation was found between the flow rate and concentrations of amylase and protein. The higher flow rate, plasma level of IRS, and bicarbonate concentration at the beginning of the examination may be due to the presence of acid and/or bile in the duodenal contents shortly after the endoscope enters the duodenum. Later in the procedure the levels have stabilized, which indicates that little or no acid or bile is passing into the duodenum. It is also concluded that secretin may be one factor responsible for the basal pancreatic secretion in man.