The secretion of electrolytes and enzymes by the pancreas of the anaesthetized cat.

Abstract

1. The bicarbonate concentration in cat pancreatic juice falls and the chloride concentration increases at slow secretory rates. The concentration of sodium and potassium remain constant at all secretory rates.2. Acetazolamide reduces the maximal rate of secretion markedly, and the maximal bicarbonate concentration slightly, but does not alter the reciprocal relationship between bicarbonate and chloride at slow rates of flow.3. By perfusion of the main duct it has been shown that there is a loss of bicarbonate and a gain of chloride across the duct wall due to a passive process of exchange diffusion. It is suggested that this may account for a substantial part of the flow-dependent changes in bicarbonate and chloride concentrations in the intact gland.4. The enzyme content of pancreatic juice is made up of a small continuous basal output, to which may be added a much larger secretion in response to hormonal stimulation.5. From analysis of successive small samples of juice it has been found that the response to single injections of pancreozymin lasts a very short time, during which the secretory cells release enzymes in a small volume of chloride-containing fluid.6. It is concluded that in the cat pancreatic secretion consists of an isosmolar primary secretion mostly of sodium bicarbonate, to which is added small amounts of a chloride-containing enzyme secretion. This fluid is modified, particularly at slow flow rates, by transductal exchange of chloride and bicarbonate which, at least in the main duct, is passive in nature.