Duodenal aspirates were obtained before, during, and after stimulation with
secretin-cholecystokinin in 26 patients whose pancreatic function was classified as normal,
moderately reduced, or severely reduced. The activities of γ-glutamyl transferase (GGT), alkaline
phosphatase (ALP), and 5'-nucleotidase (5NT) in the aggregated duodenal aspirate collected
10—40 min after stimulation showed marked overlap between the functional groups and
lacked diagnostic value. For all three enzymes, the peak response occurred later in the severely
impaired group than in those with normal pancreatic function. The three enzymes showed
significant positive correlations with each other, and were negatively correlated with the output
of trypsin and Chymotrypsin and, in contrast with these proteolytic enzymes which were
reduced in pancreatic disease, GGT, ALP, and 5NT all tended to increase with pancreatic
disease. Contrary to a previous report, GGT did not serve as a useful index of pancreatic
cancer in this study.