Analysis of NaC1 permeability in rabbit gall-bladder

In rabbit gall-bladder NaC1 is both actively and passively transported. A phenomenological description of solute and solvent (water) active and passive flows across a biological membrane can be made explicitly considering the dependence of matter flows upon the rate of metabolic reactions, or introducing a generalized chemical potential including a term accounting for active transport, or making the hypothesis that solute flow can be splitten in two superimposed and thermodynamically coupled active and passive components. By the latter approach, by means of transformation of flows and forces at constant temperature and in absence of electric field, it was obtained for volumetric flow (Jv): Jv = LpΔp+LpdΔπ+LpaXa where Δp, Δπ, Xa are respectively the hydrostatic pressure difference, the osmotic pressure difference and a force related to active transport. Lp, Lpd and Lpa are the phenomenological coefficients. This equation can be experimentally tested.