Figure 3
From: Differential modulation of cellular death and survival pathways by conjugated bile acids
Expression of recombinant apical sodium/bile acid transporter (asbt) in CHO cells. (A) The 1.7 kb recombinant asbt mRNA is readily detectable in total RNA (10 μg) of selected CHO.asbt clones. Note the absence of this band in total RNA of CHO cells. (B) The recombinant asbt protein is also readily detectable by immunoblotting in total lysates (20 μg) of CHO.asbt cells, but not of CHO cells. The recombinant asbt protein is similar in size to the authentic asbt detectable in rat ileal cell extracts. (C) CHO.asbt cells show saturable and concentration dependent uptake of taurocholic acid (TCA). The apparent Km for TCA range from 22.4 to 25.9 μM. (D) Time dependent uptake of TCA in CHO.asbt and CHO cells. TCA uptake reaches a maximum at 10 min. (E) Efflux of TCA from CHO.asbt.49 and CHO.asbt.35 cells. The cells were incubated with 25 μM [3H]-TCA for 20 min to label the intracellular pool of bile acids. The amount of radioactivity that remains associated with the cells after the removal of radiolabeled TCA from the medium is shown. The values represent means ± SD (n = 3). The experiments in (A), (B), (C), and (D) were repeated twice with similar results.