Role of cholecystokinin in intestinal phase of human pancreatic secretion

In this study we have utilized a sensitive and specific radioimmunoassay for cholecystokinin (CCK) to determine the effects of a jejunal infusion (5 cc/min) of amino acids (44 g/liter), saline, and amino acids with intravenous atropine (20 micrograms X lg-1 X hr) on pancreatic exocrine secretion. Amino acids were found to stimulate pancreatic output of trypsin and release CCK, while a saline infusion at the same rate and osmolality (320 mosm/liter) failed to do so. In the presence of atropine, the amino acid infusion did not stimulate the pancreatic output of trypsin, despite an augmented CCK release. The total CCK released above baseline was greatest with the infusion of amino acids with atropine, while the total trypsin output above baseline was greatest with the infusion of amino acids. These results indicate that CCK release is not under cholinergic control and that cholinergic blockade inhibits pancreatic secretion by interrupting stimulating cholinergic fibers to the pancreas.