Fig. 6.

A: competition assay for [³H]TCA transport. Huh7 cells transfected with skSlc10a1, hNTCP, or empty vector were incubated for 10 min in Na⁺ medium supplemented with 10 µM [³H]TCA with or without competitor. Cells were treated with 1 µM cyclosporin A, 10 µM dehydroepiandrosterone (DHEA), 10 µM pregnenolone (PREG), and all the other competitors were 2 µM. Background levels derived from cells transfected with vector control were subtracted, and uptake measurements were normalized to protein concentration. Transport activity from a noncompetitor control was set at 100%. All values represent at least three independent experiments and are expressed as means ± SD. *P < 0.05, noncompetitor control vs. competitor; #P < 0.05, skSlc10a1 vs. hNTCP; n ≥ 3. Uptake assays for [³H]DHEAS (B) and [³H]estrone-3-sulfate (C) in Huh7 cells transfected with expression vector for hNTCP, skSlc10a1, or empty vector were incubated for 10 min in Na⁺ medium with 0.5 µM DHEAS or estrone-3-sulfate. Values are expressed as means ± SD; n = 3. *P < 0.05, compared with empty vector in paired analysis.