Pancreatic protein secretion and gastrointestinal hormone release in response to parenteral amino acids and lipid in dogs

Parenteral nutrition has been advocated for and used in clinical situations in which provision of calories without stimulation of pancreatic secretion is desired. A recent report, however, provided evidence for substantial stimulation of pancreatic secretion after parenteral administration of amino acids and fat. We have studied the effect of intravenous administration of crystalline amino acids and lipid on pancreatic protein secretion and release of gastrointestinal hormones in five dogs with chronic pancreatic fistulas. The amino acids were given as a 4.25% solution in 5% glucose at 2 gm/hr. Parenteral fat was administered as Intralipid 10% at 3.5 ml/kg/hr. Plasma concentrations of cholecystokinin (CCK) and pancreatic polypeptide (PP) and serum concentrations of gastrin, measured by radioimmunoassay, were determined before, and at intervals during, infusion of amino acids and fat. Pancreatic juice was collected simultaneously with blood sampling, and volume and protein output were measured. Basal concentrations of CCK, PP, and gastrin were not affected by intravenous infusion of amino acids. Pancreatic protein secretion and volume were also unaffected by parenteral amino acids. Parenteral infusion of fat resulted in a significant inhibition of integrated gastrin release but had no effect on plasma concentrations or integrated release of CCK or PP. Neither the volume nor protein output of pancreatic secretion was affected by intravenous fat administration. In summary, no stimulation of pancreatic secretion or release of CCK, PP, or gastrin occurred as a result of parenteral amino acid or fat administration. There is, therefore, no contraindication to the use of parenteral nutrition in situations in which it is desirable to keep the pancreas at rest.