Concentration-dependent inhibitory effect of ethinylestradiol, fidaxomicin, troglitazone sulfate, norgestimate, atorvastatin, glycochenodeoxycholate and troglitazone on OSTα/β-mediated DHEAS transport. OSTab and Mock cells were preincubated with inhibitors for 10 min (Method 1; 0–200 μM) prior to the 30-s uptake with [3H]-dehydroepiandrosterone sulfate (DHEAS; 200 nCi/ml; 4 μM) at 37°C. Data are expressed as percentage of vehicle control; each value represents the mean ± SD of two independent experiments, each performed in triplicate. For troglitazone, only one experiment is shown (mean ± range).