Bicarbonate and chloride transport in relation to the acidification or alkalinization of the urine.

Although the electrogenicity of the active reabsorption of sodium and bicarbonate (or secretion of protons) has been well-established in the short-circuited turtle bladder preparation, the nature of the active reabsorption of chloride and secretion of bicarbonate has been controversial. These processes have been ascribed to the separate actions of two discrete electrogenic pumps or to the single action of a metabolically driven electroneutral anion exchange mechanism. The present report deals with these transport processes per se; with the relations among serosal bicarbonate,glucose, and the reabsorption of Na and Cl; and finally with the application of the Heinz model for inversion of an active transport as a tentative single mechanism for the alkalinization and acidification of the urine.