Relationship Between Protein Nitrogen, Proteolytic, Amylolytic and Lipolytic Enzymes in Canine Pancreatic Juice Obtained Under Various Conditions of Stimulation

¹ From the Samuel S. Fels Research Institute, Temple University School of Medicine, Philadelphia, Pennsylvania

Pancreatic secretion obtained from a dog with a permanent pancreatic fistula in response to each of four different kinds of test meals was analyzed for proteolytic, amylolytic and lipolytic activity with the view of studying possible correlation between the concentrations of the enzymes and protein nitrogen, and also possible effect of variation in composition of the test meals on these constituents. The enzyme activities were determined by phototurbidimetric methods, some of which were developed in this laboratory. Statistically significant deviations from proportionality between each of the enzymes and protein nitrogen, and also from the secretion of the enzymes in parallel concentrations occurred in specimens secreted in response to the same kind of test meal with day-to-day variation being the main contributing factor. With the exception of the relationship between amylase and protein nitrogen, deviations from enzyme-protein nitrogen proportionality and from the parallel secretion of the enzymes in specimens secreted in response to different test meals were not significantly greater than the daily variations which occurred in response to the same type of test meal. All these variations did not conform with any of the following widely held theories: a) proportionality between each of the enzymes and protein nitrogen, b) secretion of all enzymes in parallel concentrations regardless of composition of the test meal, and lastly c) purposive adaptation of concentrations of individual enzymes to the kind of food ingested. No evidence elucidating the physiologic mechanism of the variations observed was obtained.