Role of the red cell membrane in oxygen uptake.

The rate at which red blood cells take up O2 or CO as measured in a rapid reaction apparatus is considerably less than predicted from solution of the equations for diffusion and chemical reaction in a layer of hemoglobin solution about the same thickness as the red cell. Nicolson and Roughton (1951) showed that this discrepancy could be accounted for by postulating that the red cell membrane is an important barrier to gas uptake. Sinha (1969) measured the rate of O2 uptake by single red cells located near a gas-plasma interface. The equations for diffusion and chemical reaction of O2 in a membraneless layer of hemoglobin solution for conditions that correspond to Sinha's experiments are solved. The calculated time course of O2 uptake fits the experimental data sufficiently well to suggest that the resistance of the red cell membrane to O2 diffusion is not an important limiting factor. Also analyzed in this way is the data of Carlson and Comroe (1958). The author finds that calculations predict a faster rate of CO uptake by biconcave disc shaped red cells than was observed experimentally, but that calculations for sphered red cells agree well enough with experimental data that membrane CO permeability may not be primary in limiting CO uptake by spherocytes.