Role of bile and trypsin in the release of cholecystokinin in humans.

The influences of (a) intraluminal bile deficiency due to common bile duct obstruction and (b) intraduodenal administration of pooled own bile and bovine trypsin on the plasma cholecystokinin (CCK) response to oral fat (Lipomul) ingestion were investigated in seven patients with periampullary tumors and 10 healthy volunteers. Basal and fat-stimulated plasma CCK levels in the patients were significantly higher than in the normal controls. Intraduodenal administration of pooled own bile at a rate of 100 ml/h significantly suppressed both basal and fat-stimulated CCK secretion. Simultaneous administration of pooled own bile (100 ml/hr) and bovine trypsin (600 mg/hr) caused further significant suppression of fat-stimulated CCK secretion compared with that under bile infusion alone. These results indicate that both intraluminal bile and trypsin exert a negative feedback effect on the release of CCK in humans.