Effect of alanine substitution on uptake of high concentration of estrone-3-sulfate.

<p>Transport of 100 nM or 50 µM E-3-S in HEK293 cells expressing OATP1B1 or its alanine-substituted mutants was measured. Net uptake was obtained by subtracting the uptake of cells transfected with empty vector from cells expressing wild-type OATP1B1 or its mutants. Uptake of mutants was normalized to transporter expression at the cell surface in the same batch of cells and quantified relative to that of the wild-type. The results shown are means ± S.E. (<i>n</i> = 3). Asterisks indicate values that are significantly different (<i>p</i><0.05).