Uptake of [3H]bilirubin in freshly isolated rat hepatocytes: role of free bilirubin concentration

FEBS Letters

Guibert, Edgardo E.²  Pascolo, Lorella¹  Rodriguez, Joaquin V.²  Ostrow, J.Donald³  Tiribelli, Claudio¹  Mediavilla, Maria Gabriela¹ 

[1] Centro Studi Fegato, Department of Biochemistry, Biophysics and Chemistry of Macromolecules (BBCM), University of Trieste, Via Giorgeri 1, 34127 Trieste, Italy;Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, 2000 Rosario, Argentina;Gastroenterology/Hepatology Section, Medical Service (111-GI-A), DVA Puget Sound Health Care System, Seattle, WA 98108-1597, USA

关键词: Unconjugated bilirubin;    Hepatocyte;    Saturation;   

DOI  :  10.1016/S0014-5793(99)01606-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Hepatocytic transport of physiological concentrations of unconjugated bilirubin (UCB) has not been determined in isolated liver cells. Initial uptake of highly purified [³H]UCB was measured in rat hepatocytes in the presence of human serum albumin at various free, unbound UCB concentrations, [UCB]. At [UCB]=42 nM (below aqueous solubility of 70 nM), uptake was strictly temperature dependent; this was much less evident at [UCB]=166 nM (supersaturated). At low, physiological UCB concentrations, specific UCB uptake showed saturative kinetics with an apparent K _m of 41 nM, indicating carrier-mediated transport. With aqueous supersaturation, UCB entered hepatocytes mainly by passive diffusion.

【 授权许可】

Unknown