AJP - Cell Physiology, Vol 233, Issue 3 104-C110, Copyright © 1977 by American Physiological Society
Membrane permeability of isolated lung cells to nonelectrolytes
R. A. Garrick and W. R. Redwood
Mixtures of viable endothelial and epithelial cells were separated by
enzymatic digestion from rabbit lung and recovered by centrifugation. The
cells were mixed with an extracellular marker and packed by centrifugation
into small-diameter polyethylene tubing and pulsed with tritiated water and
14C-labeled alcohols. Calculation of diffusion coefficients for the packed
cell column (D), intracellular material (D2), and extracellular fluid (D1)
was based on a local steady-state one-dimensional diffusional model.
Permeability coefficients were: tritiated water, 288 X 10(-5) cm s-1;
methanol, 385 X 10(-5) cm s-1; ethanol, 214 X 10(-5) cm s-1; propanol, 277
X 10(-5) cm s-1; and hexanol, 1255 X 10(-5) cm s-1. The permeability
coefficients of these aliphatic alcohols show a minimum at ethanol with
hexanol having the highest value of all substances tested. The results
support the concept of parallel aqueous and lipid pathways for small
solutes in the plasma membrane. Study of the permeability properties of
isolated lung cells can provide information on the cellular pathway in the
transcapillary transport of water and solutes in the lung.
