Effect of duodenectomy on interdigestive pancreatic secretion, gastrointestinal motility, and hormones in dogs.

We tested the hypothesis that the duodenum is necessary to coordinate interdigestive pancreatic trypsin secretion with gastrointestinal motility and determined whether duodenectomy altered interdigestive cycles of plasma motilin and pancreatic polypeptide and their relationship to trypsin secretion and motility. Consequently, in normal and duodenectomized dogs, we measured trypsin secretion, gastrointestinal motility, and plasma concentrations of motilin and pancreatic polypeptide during the interdigestive period. After duodenectomy, peaks of trypsin secretion continued to cycle at normal intervals (102 +/- 15 min), but the amounts of trypsin were reduced during peaks of secretion (P = 0.02) and throughout the entire cycle (P = 0.02). Trypsin secretory cycles after duodenectomy, however, were not coordinated with cycles of interdigestive motility, and the plasma concentrations of motilin (P = 0.02) and pancreatic polypeptide (P = 0.05) were reduced and had no cyclic pattern. In addition, we confirmed that duodenectomy alters canine interdigestive antral motility, interrupts coordination between antral and intestinal motility, and shortens the period of jejunal migrating motor complexes. We conclude that duodenectomy disrupts the relationship between the cycles of interdigestive gastrointestinal motility and trypsin secretion and reduces the amount of interdigestive trypsin secretion. These effects of duodenectomy may be due to interruption of the duodenopancreatic neural connections or the hormonal abnormalities we have described. The loss of the cyclic pattern of plasma pancreatic polypeptide after duodenectomy suggests that the duodenum controls the release of pancreatic polypeptide by either a neural or hormonal mechanism.