Plasma cholecystokinin concentration in patients with chronic pancreatitis measured by bioassay

We developed a specific and sensitive bioassay for measuring plasma cholecystokinin (CCK) in human and investigated CCK response after a test meal in patients with chronic pancreatitis. Treatment with cycloheximide increased the sensitivity and responsiveness of isolated rat pancreatic acini to CCK-octapeptide (CCK-8) and thus plasma levels of CCK-8 as low was 0.17pM were detectable. Fasting plasma CCK levels in normal subjects as CCK-8 equivalents were 0.75±0.25pM and rose to a peak of 6.2±0.68pM at 45min after a test meal consisting of 400ml milk and 2 boiled eggs. Basal and stimulated plasma levels of CCK-8 in patients with non-calcified chronic pancreatitis were significantly higher than those in normal subjects. In contrast, postprandial responses of plasma CCK-8 in patients with calcified chronic pancreatitis was significantly low compared to those in contraol subjects, although basal plasma levels were not significantly different from those in controls.