Hepatic bilirubin uptake in the isolated perfused rat liver is not facilitated by albumin binding.

Hepatic bilirubin uptake in the isolated perfused rat liver is not facilitated by albumin binding.

Bilirubin uptake by the liver is a rapid process of high specificity that has kinetic characteristics which suggest carrier-mediation. In the circulation, bilirubin is readily bound to albumin, from which it is extracted by the liver. Although several studies suggested that it is the small, unbound fraction of bilirubin which interacts with hepatocytes and is removed from the circulation, recen...

Albumin binding of unconjugated [3H]bilirubin and its uptake by rat liver basolateral plasma membrane vesicles.

Using highly purified unconjugated [3H]bilirubin (UCB), we measured UCB binding to delipidated human serum albumin (HSA) and its uptake by basolateral rat liver plasma membrane vesicles, in both the absence and presence of an inside-positive membrane potential. Free UCB concentrations ([Bf]) were calculated from UCB-HSA affinity constants (K'f), determined by five cycles of ultrafiltration thro...

Uptake of free choline by isolated perfused rat liver.

The uptake of free choline by isolated perfused rat liver was characterized. A saturable uptake mechanism [Ka = 0.17 +/- 0.07 mM (SD); Vmax = 0.84 +/- 0.16 mumol/min X g dry weight] and a nonsaturable mechanism (through which uptake is proportional to choline concentration in the perfusate) were identified. Most of the choline transported into hepatocytes was converted to betaine, phosphorylcho...

Imatinib metabolism and disposition in isolated rat perfused liver

Imatinib is an orally administered tyrosine kinase inhibitor which inhibits the Bcr-Abl protein-tyrosine kinase with high selectivity. Imatinib is rapidly absorbed from the gut, after oral intake and has an almost absolute bioavailability of 98%. The metabolism of imatinib is mediated by the cytochrome P450 (CYP) isoenzymes in the liver and gut wall. CGP74588 is a major active metabolite of ima...

Bilirubin formation in the liver from nonhemoglobin sources. Experiments with isolated, perfused rat liver.