PANCREATIC SECRETORY RESPONSE TO INTRAJEJUNAL TRYPTOPHAN - STUDIES INDOGS WITH AN AUTOTRANSPLANTED ENTIRE JEJUNOILEUM

In two sets of dogs with gastric, duodenal, and jejunal fistulas, we s tudied the effect of atropine (14 nmol/kg/h) on the pancreatic secreto ry response to intrajejunal tryptophan (0.12-10.0 mmol/h; given agains t a secretin background) before (n = 7) and after extrinsic denervatio n of the jejunoileum (orthotopical autotransplantation; n = 6). Plasma levels of cholecystokinin were determined by radioimmunoassay. The in cremental bicarbonate response to tryptophan was not significantly dif ferent between the two sets of dogs. Atropine had no effect on the inc remental bicarbonate response to tryptophan. In both sets of dogs, int rajejunal tryptophan caused a dose-dependent increase in pancreatic pr otein output, which was reduced by atropine. The tryptophan-stimulated levels of plasma cholecystokinin were not significantly altered by de nervation and/or atropine. We conclude that in dogs (1) intrajejunal t ryptophan stimulates pancreatic bicarbonate and protein secretion via release of hormones, (2) extrinsic denervation of the jejunoileum does not significantly alter the incremental bicarbonate and protein respo nses to intrajejunal tryptophan, (3) the cholinergic intrinsic nerves of the jejunoileum and the hormone cholecystokinin are probably involv ed in control of the pancreatic protein response to tryptophan, and (4 ) the release of cholecystokinin by intrajejunal tryptophan does not d epend on the extrinsic and intrinsic cholinergic nerves of the jejunoi leum.