PHENOMENOLOGIC EVALUATION OF CO2-DIFFUSION RESTRICTION IN KIDNEY-TUBULES STUDIED IN AN ARTIFICIAL MEMBRANE SYSTEM

The chemical course in a multi‐membrane system with interacting H+ and HCO3 ions has been described phenomenologically as an analogy of the neutralisation reaction between secreted H+ and filtered HCO3 ions in the proximal tubules of the kidney. It was shown that the produced CO2 gave the highest PCO2 in the asymmetrically placed reaction centre, which favours a build‐up of a high intratubular PCO2. The CO2 transport was dependent on the rate‐limiting permeation of the reacting ions, and the permeation could be increased by the influence of solutions of macro molecules such as carbonic anhydrase, albumin and dextran. © 1979 Scandinavian Physiological Society