Measurements of exocrine proteins in the pig pancreas using microdialysis

The authors adapted microdialysis for the study of intrapancreatic exocrine proteins. Immunoreactive cationic and anionic trypsinogen were continuously measured after the insertion of one probe inside the pig pancreas and another placed under the peritoneum on the anterior surface of the gland. The concentration initially declined in the dialysate from the intrapancreatic probe, followed by an increasing tendency until 120 minutes after the insertion, after which a decline to a relative steady state after four to six hours was observed. A dialysate with a lower concentration of enzymes was obtained from the probe on the pancreatic surface. In order to study the turnover of an exogenously administered substance, a microdialysis probe was inserted into the pancreas and human recombinant pancreatic secretory trypsin inhibitor was injected into the pancreatic duct. The inhibitor was cleared from the pancreas with an intrapancreatic half-life of approximately 45 minutes. Membrane function, measured in vitro before and after use in vivo, was not significantly affected after seven hours in the pig pancreas.