Influence of treatment with pancreatic extracts on pancreatic enzyme secretion

We have evaluated the effects of porcine pancreatic extracts on human pancreatic secretion. Ten male volunteers were intubated with a 4-lumen jejunal tube to collect gastric and duodenal secretions separately via the first and third tube, to infuse PEG 4000 distal the pylorus via the second tube and to apply porcine pancreatic extracts via the fourth tube distal the ligament of Treitz. Pancreatic extracts were given four times at 40 minute intervals; the first two as active enzymes and subsequently as heat denatured proportions. Secretin was continuously infused intravenously (0.5 E/kg bw/h) to achieve minimal pancreatic flow. Lipase, amylase, trypsin, chymotrypsin, volume, and bicarbonate were measured in duodenal contents in eight pooled 15 minute fractions. Three subjects who received HEPES-Ringer buffer instead of pancreatic enzymes served as controls. Plasma cholecystokinin (CCK) was measured using a sensitive bioassay. Both active and heat denatured pancreatic extracts caused a small but significant increase in amylase and chymotrypsin secretion. Basal plasma CCK values were 0.85 (0.05) pM. After intrajejunal instillation of either active or heat denatured pancreatic extracts plasma CCK rose to 3.25 (0.30) pM and to 3.28 (0.36) pM respectively. In a second group of five volunteers, plasma CCK concentrations were measured after a test meal. On day 1, volunteers received a liquid fat and protein rich meal and on day 2, the same test meal containing porcine pancreatic extracts. In both cases, a similar increase in plasma CCK was observed. We conclude that therapy with pancreatic extracts stimulate pancreatic enzyme secretion. This may be mediated through release of CCK.