Relationship between Bicarbonate, Chloride, and Volume Flow at High Secretory Rates in the Pancreatic Juice of the Dog

Large doses of secretin result in increasing flow rates of pancreatic juice, along with a drop of bicarbonate concentration and a rise of chloride concentration. This dissociation is the result of pharmacological properties of the secretin itself. Although the exchange theory can account for the secretory pattern observed at low and moderate flow rates, the facts reported here at high flow rates are best accounted for by a two-component hypothesis, both components of the juice (bicarbonate-rich secretion and chloride-rich secretion) being stimulated by secretin and unequally sensitive to this stimulation. Whether transport of water molecules or of chloride ions in the chloride-rich secretion is directly stimulated by large doses of secretin cannot be decided.