Mechanism of release of endogenous cholecystokinin by jejunal amino acid perfusion in man.

Ertan et al have shown that the perfusion of the proximal jejunum with a mixture of amino acids (MAA) in physiological concentration releases endogenous cholecystokinin (CCK) in man. In the present experiment, we investigate the mechanism by which jejunal MAA perfusion mediates an increase in exocrine pancreatic and biliary secretions. The effects of a bolus of topical anesthetic (oxethazaine, 0.5 mg/kg of 0.4% solution) or the simultaneous jejunal perfusion of a topical anticholinergic agent (atropine, 1 mg/liter) were studied in the same five normal patients on different days. Suppression of the response to jejunal MAA perfusion but not to intravenous infusion of CCK or jejunal saline perfusion, was noted in these normal subjects following jejunal application of oxethazaine and atropine. These results suggest a local involvement of the cholinergic mechanism for the endogenous release of CCK, while exogenous CCK acts directly on the pancreatic cells.