AJP - Cell Physiology, Vol 232, Issue 3 132-C137, Copyright © 1977 by American Physiological Society
Effect of pulmonary edema on drug transport and binding in rat lung
T. H. Gardiner and F. R. Goodman
The pulmonary absorption and uptake of (35S)phenol red ((35S)PR was
measured in anesthetized rats with alpha-naphthylthiourea- (ANTU) induced
lung edema. When (35S)PR solution was injected through a tracheal cannula
in control animals and the percentage of the tracheal cannula in control
animals and the percentage of the dose unabsorbed plotted
semilogarithmically against time, an apparent first-order absorption rate
was obtained. In contrast, in rats with ANTU-induced edema, the absorption
time curve showed at least two different first-order components. Increasing
the concentration of (35S)PR from 0.01 to 3 mM resulted in a decrease in
the percentage absorption of the compound in controls compared with a
relatively constant percentage absorption in edematous lungs. (35S)PR
uptake by lung slices from ANTU-treated rats was decreased in the presence
of IAA and a N2 atmosphere, and the dye accumulated at a faster rate and to
a greater extent than in controls. The results suggest that although
energy-dependent drug transport mechanisms remain intact, the porosity of
the absorbing membranes and the extent of drug binding in the lung are
increased markedly in the presence of edema.
