UPTAKE OF ORGANIC-ANIONS BY HEPATOCYTE MONOLAYERS - CODIFFUSION VERSUS FACILITATED DISSOCIATION

We used the clearance ratio test to determine whether the presence of albumin enhances the uptake of palmitate by hepatocyte monolayers. If uptake is facilitated, then the ratio of palmitate clearance by hepato cytes in the presence of 600 and 300 mu M albumin (i.e. Cl-t600/Cl-t30 0) will exceed the square root of the ratio of the unbound fractions a t 600 and 300 mu M albumin (i.e., root alpha(600)/alpha(300)). The lat ter value was determined using the heptane-water partitioning techniqu e. The hepatocyte clearance ratio (0.92 +/- 0.06) exceeded the predict ed value (0.80) by 15% (p < 0.05). The observed clearance rate also ex ceeded that predicted by the diffusion-reaction model.