Effect of albumin binding on the hepatic transport of rose bengal: surface-mediated dissociation of limited capacity.

We have studied the steady-state removal of rose bengal by perfused rat livers to decide whether the tight association of this anion with albumin is consistent with the conventional view that only the free fraction in the sinusoidal lumen is available for hepatic transport. The results show that the concentration of free dye is not nearly high enough to account for the observed removal rate. From these observations we argue that the liver cell surface reduces the affinity of rose bengal for albumin by a factor of approximately 100 below that observed in free solution. The findings extend and refine the results of a similar experiment with taurocholate we reported previously and they confirm the suggestion by others that the dissociation mechanism displays saturation kinetics as the albumin concentration increases.