Pancreatic enzyme response to secretin and cholecystokinin-pancreozymin in the rat.

1. The report describes a new technique for collecting pancreatic juice in anaesthetized rats. The technique, which involves perfusion of the duodenum, is particularly suitable for analysing the characteristics of pancreatic enzyme secretion. To ensure stable secretory conditions, the rats were kept at 30 degrees C.2. Different combinations of secretin and cholecystokinin-pancreozymin have been given by continuous intravenous infusion and the patterns of secretion of amylase and trypsin have been defined.3. Maximal secretion of the pancreatic enzymes was observed with 60 IU/kg.hr CCK-PZ (amylase) or 120 CU/kg.hr (trypsin) combined with 0.5 CU/kg.hr (secretin).4. Pancreatic enzyme secretion in response to submaximal stimulation with CCK-PZ was potentiated by secretin.5. Supramaximal stimulation with CCK-PZ resulted in significantly less secretion of pancreatic enzymes than in response to maximal stimulation.6. The pancreatic secretion of enzymes was poorly sustained during constant-rate stimulation with intravenous hormones, at all dose rates.7. The significance and possible mechanisms of the biphasic pattern of enzyme secretion in response to increasing doses of stimulant hormones and the fall-off in enzyme secretion during constant-rate stimulation are discussed.