The osmotic permeability of isolated calf pulmonary artery endothelial cells

Abstract

Osmotic permeability coefficients, P F , for water in isolated calf pulmonary artery endothelial cells determined over the temperature range 41 to 20°C are 311 · 10 −5 cm · s −1 at 37°C and 159 · 10 −5 cm · s −1 at 20°C. The value at 37°C is close to that reported earlier for the diffusional permeability coefficient, P D . The P F /P D ratio is 1.0 at 37°C. The P F values are within the range of values extrapolated for filtration permeability in pulmonary endothelium. The temperature dependence expressed as the activation energy is 7.2 kcal · mol −1. The product of hydraulic conductivity, L p (or P F ) and of viscosity changes in water is not constant from 37 to 20°C. These results can be interpreted to indicate a similar pathway for water whether under diffusional or osmotic gradients.