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 Km of 41 nM, indicating carrier-mediated transport. With aqueous supersaturation, UCB entered hepatocytes mainly by passive diffusion.
Uptake of [3H]bilirubin in freshly isolated rat hepatocytes: role of free bilirubin concentration
PASCOLO, LORELLA;TIRIBELLI, CLAUDIO
1999-01-01
Abstract
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 Km of 41 nM, indicating carrier-mediated transport. With aqueous supersaturation, UCB entered hepatocytes mainly by passive diffusion.Pubblicazioni consigliate
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