Uptake of pramipexole into hOCT3-HEK and mock cells. A, Pramipexole uptake was greater into hOCT3-HEK cells than into mock cells. B, Apparent permeability of pramipexole versus concentration is plotted for pramipexole uptake into hOCT3-HEK cells and mock cells. Also plotted is the apparent permeability of TEA at 71.3 μM into hOCT3-HEK cells and mock cells. C, Inhibition of pramipexole uptake (10 μM) into hOCT3-HEK and mock cells by 100 or 200 μM corticosterone. ***, p < 0.001, compared with hOCT3-HEK cells not treated with corticosterone. Error bars denote SEM.