Hepatic uptake of bilirubin diglucuronide: Analysis by using sinusoidal plasma membrane vesicles

Yukihiko Adachi, Jayanta Roy-chowdhury, Namita Roy-chowdhury, Rolf Kinne, Thao Tran, Hiroaki Kobayashi, Irwin M. Arias

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Abstract

In order to characterize the mechanism for bilirubin transport in the liver, the uptake of bilirubin diglucuronide (BDG) into purified sinusoidal plasma membrane vesicles was investigated. BDG uptake was saturable, and was inhibited by sulfobromophthalein and unconjugated bilirubin, but was not affected by sodium taurocholate. BDG uptake was sodium-independent and was stimulated by intravesicular bilirubin or BDG (trans-stimulation). BDG transport showed strong potential sensitivity; vesicle inside-negative membrane potential created by different anion gradients inhibited BDG uptake whereas vesicle inside-positive membrane potential generated by potassium gradients and valino-mycin markedly stimulated BDG transport. These data suggest that BDG, sulfobromophthalein, and probably unconjugated bilirubin share a common transporter in liver cells which is sodium independent, membrane-potential-dependent and capable of exchange. The direction of transport in vivo may be governed by the intracellular concentration of BDG and of other yet unidentified organic an ions sharing this transporter.

Original languageEnglish (US)
Pages (from-to)749-754
Number of pages6
JournalJournal of Biochemistry
Volume107
Issue number5
DOIs
Publication statusPublished - May 1990

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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