Transport by vesicles of glycine- and taurine-conjugated bile salts and taurolithocholate 3-sulfate: a comparison of human BSEP with rat Bsep

Biochim Biophys Acta. 2005 Dec 30;1738(1-3):54-62. doi: 10.1016/j.bbalip.2005.10.006. Epub 2005 Nov 15.


The bile salt export pump (BSEP) of hepatocyte secretes conjugated bile salts across the canalicular membrane in an ATP-dependent manner. The biliary bile salts of human differ from those of rat in containing a greater proportion of glycine conjugates and taurolithocholate 3-sulfate (TLC-S). In the present study, the transport properties of hBSEP and rBsep were investigated using membrane vesicles from HEK293 cells infected with recombinant adenoviruses containing hBSEP or rBsep cDNA. ATP-dependent uptake of radiolabeled glycine-, taurine-conjugated bile salts, and [(3)H]cholate was observed when hBSEP or rBsep was expressed. Comparison of initial uptake rates indicated that for both transporters, taurine-conjugated bile salts were transported more rapidly than glycine-conjugated bile salts, however, hBSEP transported glycine conjugates to an extent that was approximately 2-fold greater than rBsep. In addition, [(3)H]TLC-S was significantly transported by hBSEP, and hardly transported by rBsep. The mean K(m) value for the uptake of [(3)H]TLC-S by hBSEP was 9.5+/-1.5 microM, a value similar to that for hMRP2 (8.2+/-1.3 microM). In conclusion, both hBSEP and rBsep transport taurine-conjugated bile salts better than glycine-conjugated bile salts, but hBSEP transports glycine conjugates to a greater extent as compared to rBsep. TLC-S, which is present in human bile but not rodent bile, is more avidly transported by hBSEP compared with rBsep.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 11
  • ATP-Binding Cassette Transporters / metabolism*
  • Animals
  • Bile Acids and Salts / chemistry
  • Bile Acids and Salts / metabolism*
  • Biological Transport
  • Cell Membrane / metabolism
  • Cells, Cultured
  • Glycine / chemistry
  • Glycine / metabolism
  • Humans
  • Kinetics
  • Multidrug Resistance-Associated Protein 2
  • Rats
  • Species Specificity
  • Taurine / chemistry
  • Taurine / metabolism
  • Taurocholic Acid / pharmacokinetics
  • Taurolithocholic Acid / analogs & derivatives*
  • Taurolithocholic Acid / metabolism
  • Transport Vesicles / metabolism*


  • ABCB11 protein, human
  • ABCC2 protein, human
  • ATP Binding Cassette Transporter, Subfamily B, Member 11
  • ATP-Binding Cassette Transporters
  • Abcb11 protein, rat
  • Bile Acids and Salts
  • Multidrug Resistance-Associated Protein 2
  • taurolithocholic acid 3-sulfate
  • Taurine
  • Taurolithocholic Acid
  • Taurocholic Acid
  • Glycine