Output-dependent non-parallel enzyme secretion of the human pancreas

In order to study the question as to whether the enzyme ratios in the pancreatic juice change with the secretion rate, we analysed the enzyme outputs of 20 healthy volunteers under combined stimulation with varying doses of cholecystokinin (0; 0.5; 1.0 or 1.3 IDU X kg-1 X h-1), administered in random order, plus a constant dose of secretin (0.5 CU X kg-1 X h-1). The outputs of the individual enzymes correlated significantly (p less than 0.0001) to the corresponding amylase outputs in the form of power model regressions. Mathematical transformation of these curvilinear regressions permitted a comparison of their courses. This analysis revealed that the enzyme ratios in the pancreatic secretion change continuously at increasing outputs in favour of lipase greater than chymotrypsin greater than amylase. The shift in the ratio of lipase to trypsin and to amylase and that of chymotrypsin to amylase was significant (p less than 0.01).