Hepatic accumulation and intracellular binding of conjugated bilirubin

Allan W. Wolkoff, J. N. Ketley, J. G. Waggoner, P. D. Berk, W. B. Jakoby

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

After the intravenous injection of unconjugated [ 3H]bilirubin into normal Sprague-Dawley and Wistar R rats, radiolabeled bile pigments rapidly accumulated in the liver. By 1.5 min after injection an average of 36% of the injected isotope was present in liver homogenates. Between 3 and 15 min, 37-64% of the total intrahepatic radiolabeled bilirubin was conjugated, as demonstrated by extraction of label into the polar phase of a solvent partition system. This indicates both rapid conjugation, and accumulation of conjugated bilirubin within the liver cell. Fluorometric determination of the dissociation constants of purified bilirubin and its mono- and diglucuronides for homogeneous preparations of two human and four rat glutathione S-transferases, including ligandin, revealed avid binding of all three bile pigments to this class of proteins. Hence, the observation that the intrahepatic bile pigment pool contains substantial amounts of conjugated bilirubin can be attributed to the high binding affinities observed. Thin-layer chromatographic analysis of the 3H-pigments produced by p-iodoaniline diazotization of homogenates and cytosol demonstrated that the intrahepatic pool of conjugated bilirubin was almost exclusively monoglucuronide. Examination of radiolabeled bilirubin conjugates excreted in bile during the first 20 min after injection of [ 3H]bilirubin showed no preferential excretion of diglucuronide. These studies indicate that (a) both bilirubin and its monoglucuronide accumulate within the liver cell as ligands with the glutathione S-transferase; and (b) bilirubin diglucuronide does not significantly accumulate wihtin the general intrahepatocellular pool of protein-bound bile pigments. The latter observation is compatible with the formation and excretion of bilirubin diglucuronide directly from the canalicular pool of the liver cell.

Original languageEnglish (US)
Pages (from-to)142-149
Number of pages8
JournalJournal of Clinical Investigation
Volume61
Issue number1
StatePublished - 1978
Externally publishedYes

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Bilirubin
Bile Pigments
Liver
Glutathione Transferase
Injections
Thin Layer Chromatography
Bile
Intravenous Injections
Isotopes
Cytosol
Wistar Rats
Proteins
Observation
Ligands
bilirubin diglucuronide

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Wolkoff, A. W., Ketley, J. N., Waggoner, J. G., Berk, P. D., & Jakoby, W. B. (1978). Hepatic accumulation and intracellular binding of conjugated bilirubin. Journal of Clinical Investigation, 61(1), 142-149.

Hepatic accumulation and intracellular binding of conjugated bilirubin. / Wolkoff, Allan W.; Ketley, J. N.; Waggoner, J. G.; Berk, P. D.; Jakoby, W. B.

In: Journal of Clinical Investigation, Vol. 61, No. 1, 1978, p. 142-149.

Research output: Contribution to journalArticle

Wolkoff, AW, Ketley, JN, Waggoner, JG, Berk, PD & Jakoby, WB 1978, 'Hepatic accumulation and intracellular binding of conjugated bilirubin', Journal of Clinical Investigation, vol. 61, no. 1, pp. 142-149.
Wolkoff, Allan W. ; Ketley, J. N. ; Waggoner, J. G. ; Berk, P. D. ; Jakoby, W. B. / Hepatic accumulation and intracellular binding of conjugated bilirubin. In: Journal of Clinical Investigation. 1978 ; Vol. 61, No. 1. pp. 142-149.
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