Disparate Na+-requirement of taurocholate and indocyanine green uptake by isolated hepatocytes.

Uptake of both taurocholate and indocyanine green (ICG) by isolated rat hepatocytes was saturable and obeyed Michaelis-Menten kinetics. Only uptake of taurocholate exhibited Na+-dependence, a phenomenon compatible with active membrane transport. These findings suggest that the mechanisms responsible for hepatocellular uptake of bile acids and anionic dyes differ fundamentally.