Intracellular hydrogen ion changes and potassium movement

¹ Department of Physiology, University of Minnesota, Minneapolis, Minnesota

Intracellular hydrogen ion concentration was determined on skeletal muscle by the DMO technique in dogs subjected to various acid-base alterations. The data verified the fact that a given alteration in Pco₂ produces a larger hydrogen ion change in intracellular fluid than in extracellular fluid. In spite of this, however, the ratio (See PDF) decreased. On the basis of this change in ratio, the Donnan equilibrium would predict that potassium would move from intracellular to extracellular compartment and not in the reverse direction as had been assumed previously. Using the change in plasma potassium as the criterion of direction of movement of potassium between intracellular and extracellular fluids, the movement of potassium produced by any of the acid-base alterations which were studied was usually that which would be predicted by the Donnan equilibrium.