Stimulatory effect of pancreozymin-cholecystokinin on calcium secretion in pancreatic juice of dogs.

In four dogs with a permanent duodenal Thomas fistula the secretion of calcium, sodium, potassium, protein, and two pancreatic enzymes in pancreatic juice was studied. Infusion of secretin led to a decrease in concentration of calcium and of protein with increasing rates of fluid production. Pancreozymin-cholecystokinin was given in single injections superimposed on the secretin-stimulated flow of juice. This hormone stimulated the secretion of both calcium and enzyme protein in a parallel and closely correlated fashion. The secretion of this protein-bound calcium fraction I is assumed to occur in the acinar cell. A calcium fraction II, which was independent of protein secretion and pancreozymin stimulation, was demonstrated in concentrations of about 0.4 to 0.6 m-equiv/l. This fraction is thought to originate in the interstitial fluid. The secretion of two calcium-containing fluids is in accordance with the two-component theory of secretion proposed by Hollander and Birnbaum (1952).