Inhibition Assay: On the day of the uptake experiment, 10 mM HEPES was added to Hank's Balanced Salt Solution, and the pH was adjusted to 7.4 with TRIS (HBSSH). The assay buffer was prepared by adding 100 uM [3H]-taurocholate and 10 uM cold taurocholate to room temperature HBSSH. A separate washing buffer was prepared by adding 10 uM cold taurocholate to HBSSH (30 ml per assay plate) and placed on ice. Using 100% DMSO, 8 point, 3-fold dilution curves for each test compound was prepared starting at 200 uM. Similarly, an 8 point dose response curve was prepared of the control compound [(3R,5R)-3-butyl-3-ethyl-7,8-bis(methyloxy)-5-phenyl-2,3,4,5-tetrahydro-1,4-benzothiazepine 1,1-dioxide (Brieaddy, L. E. WO9605188, 1996)] starting at 1.8 mM. Drug plates were created by adding 3 uL of each concentration to a v-bottom 96-well plate then diluted 60-fold with 177 uL of assay buffer. Plates were removed from the incubator and allowed to cool to ambient temperature.