Macromolecule transport across glomerular capillaries: application of pore theory

Developments in the hydrodynamic theory of solute transport through porous membranes are reviewed, with emphasis on their application to macromolecule movement across capillary walls. A model that treats the capillary wall as a barrier containing uniform cylindrical pores, and permeating solutes as hard spheres, is shown to be successful in describing the size-selectivity of the glomerulus. Influences of various hemodynamic perturbations on solute transport are also accounted for by this approach. Possible extensions and modification of the theory, to account for the influence of molecular charge and other factors on glomerular permeability properties, are discussed.