Effect of parenteral amino acids on human pancreatic exocrine secretion

Abstract

Parenteral administration of amino acids has been utilized for the nutritional support of patients with a variety of gastrointestinal disorders including protracted pancreatitis and pancreatic fistulae. However, the effect of parenteral amino acid administration alone on human pancreatic secretion has not been studied. We have studied the short-term effect of parenteral administration of amino acids on pancreatic exocrine secretion in seven healthy men. A double-lumen tube was placed in the duodenum and polyethylene glycol was perfused into the proximal duodenum at the rate of 10 ml/min. A second double-lumen tube was placed in the stomach and bromsulfthalein was perfused into the cardia. Samples of duodenal contents were aspirated and gastric contents recovered during one hour of intravenous saline infusion followed by two hours of an amino acid mixture infusion. Hourly outputs of protein and pancreatic enzymes were determined, correcting for duodenogastric reflux based on concentrations of both markers in the samples. Despite an average increase of 72% in the plasma concentration of the infused amino acids, the outputs of protein, trypsin and amylase did not change significantly during amino acid infusion; the output of lipase decreased significantly during amino acid infusion. Two subjects were given intravenous secretin and cholecystokinin following amino acids; this resulted in increased outputs of protein, trypsin, and amylase in both. We conclude that the parenteral administration of amino acids to healthy young men does not stimulate pancreatic enzyme secretion as measured by the method using duodenal marker perfusion at the rate of 10 ml/min.

ESPEN guidelines on nutrition in acute pancreatitis

“…Regardless of whether the elemental diet was ingested orally, infused into the duodenum, or into the jejunum, the elemental diet resulted in less stimulation than the standard diet infused at the same level (49,(60)(61)(62)(63)(64)(65)(66). Finally, intravenous administration of protein hydrolyzates either inhibit exocrine pancretic secretory responses or they do not have any effect (67,68).…”

Nutritional support in acute pancreatitis

“…Variyam et al [26] also found that pancreatic enzyme secretion was not stimulated by parenteral amino acids, but others have demonstrated a stimulatory effect after fasting. Niederau et al [27] showed a rise in pancreatic secretion in response to parenteral amino acids, a fall with glucose infusion, and no change with lipid infusion alone.…”

Nutritional management of acute pancreatitis

“…TPN does not appear to significantly stimulate pancreatic secretions in human and animal studies. Specifically, intravenous amino acids do not stimulate pancreatic secretion in healthy men [26]. In another study, parenteral amino acids caused a rise in secretion, glucose caused a fall, and no change was reported with lipids and a mixture of all three substrates in healthy volunteers [27].…”