AJP - Cell Physiology, Vol 236, Issue 1 9-14, Copyright © 1979 by American Physiological Society

ARTICLES

Uptake of unconjugated bilirubin by isolated rat hepatocytes

T. Iga, D. L. Eaton and C. D. Klaassen

The mechanism responsible for the hepatic uptake of unconjugated bilirubin was examined in isolated rat hepatocytes from control and phenobartital-pretreated rats. The uptake was extremely rapid and the equilibrium between cell and medium was attained within 60 s with a 100-fold higher concentration in the cell than the medium. The initial velocity of uptake (Vo) exhibited a linear relationship to the bilirubin concentration in the medium. Pretreatment of cells with various metabolic inhibitors had no effect on the uptake of unconjugated bilirubin. Ouabain did significantly decrease Vo, but replacement of sodium ion with choline or lithium had no effect on bilirubin uptake. The organic acids sulfobromophthalein (112 muM) and taurocholic acid (50 (muM) and two steroidal compounds, diethylstilbestrol (50 muM) and spironolactone (50 muM), had no effect on the uptake of bilirubin. It is suggested that bilirubin gains access to the hepatocyte interior by passive diffusion into and through the lipid membrane and that intracellular binding may explain the high degree of bilirubin accumulation associated with the isolated hepatocytes.

This article has been cited by other articles:

				E. Gopal, S. Miyauchi, P. M. Martin, S. Ananth, S. R. Srinivas, S. B. Smith, P. D. Prasad, and V. Ganapathy Expression and functional features of NaCT, a sodium-coupled citrate transporter, in human and rat livers and cell lines Am J Physiol Gastrointest Liver Physiol, January 1, 2007; 292(1): G402 - G408. [Abstract] [Full Text] [PDF]

				S. D. Zucker, W. Goessling, and A. G. Hoppin Unconjugated Bilirubin Exhibits Spontaneous Diffusion through Model Lipid Bilayers and Native Hepatocyte Membranes J. Biol. Chem., April 16, 1999; 274(16): 10852 - 10862. [Abstract] [Full Text] [PDF]