Transport of bile acids in a human intestinal epithelial cell line, Caco-2.
The transport of taurocholic acid (TA) across Caco-2 cell monolayers was dependent on time in culture and reached a plateau after 28 days, at which time the apical (AP)-to-basolateral (BL) transport was 10-times greater than BL-to-AP transport. The amounts of TA inside the cells following application of 10 nM [14C]TA to the AP or BL side of the monolayers (30 min) were approximately equal (54.4 +/- 2.7 and 64.6 +/- 2.8 fmol/mg protein, respectively). AP-to-BL transport of TA was saturable and temperature-dependent. Vmax and Km for transport were 13.7 pmol/mg protein per min and 49.7 microM, respectively. The transport of TA had an activation energy of 13.2 kcal.mol-1, required Na+ and glucose. AP-to-BL transport of [14C]TA was inhibited by the co-administration (on the AP side) of either unlabeled TA or deoxycholate, but it was not reduced by the presence of unlabeled TA on the BL side.
Hidalgo
I J
IJ
Department of Pharmaceutical Chemistry, University of Kansas, Lawrence 66045.
Borchardt
R T
RT
D001647:Bile Acids and Salts / Q000378:metabolism*; D001692:Biological Transport; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D007700:Kinetics; D013656:Taurocholic Acid / Q000493:pharmacokinetics; D014407:Tumor Cells, Cultured
D001647:Bile Acids and Salts; D013656:Taurocholic Acid