INDEPENDENCE OF WATER AND SOLUTE PATHWAYS IN HUMAN RBCS

We have investigated the permeability of the human red blood cell to f our di-hydroxy alcohols, 1,2PD (1,2 propanediol), 1,3PD (1.3 propanedi ol), 1,4BD (1,4 butanediol), and 2,3BD (2,3 butanediol), and to water by using a recently developed ESR stopped-flow method which is free fr om artifacts found in light scattering methods. Numerical solutions of the Kedem-Katchalsky equations fit to experimental data yielded the f ollowing permeability coefficients: P1,2PD = 3.17 X 10(-5) CM sec-1, P 1,3PD = 1.75 x 10(-5) CM sec-1, P1,4BD = 2.05 x 10(-5) cm sec-1, P2,3B D = 7.32 x 10(-5) cm sec-1. Reflection coefficients (a) were evaluated by comparing data fit with assumed values of sigma = 0.6, 0.8 and 1.0 . In all four cases the best fit was obtained with sigma = 1.0. Treatm ent of cells with PCMBS (para-chloro mercuri-benzene-sulfonate) was fo llowed by a large (>10-fold) decrease in water permeability with virtu ally no change in alcohol permeability. We conclude that these alcohol s do not permeate the water channels to any significant extent, and di scuss some of the problems in light scattering measurements of reflect ion coefficients that could lead to erroneous values for sigma.