MC-LR uptake mediated by rtOatp1d1. (A) Immunoblot showing uptake of MC-LR mediated by transiently transfected rtOatp1d1-HEK293, ev-HEK293, non-transfected cells (non-tr.) or stable transfected human OATP1B3-HEK293. Cells were incubated with 50 nM MC-LR (+), or solvent control MeOH (−) for 1, 6 and 24 h, GAPDH has been used as reference gene; (B) and (C) Densitometric greyscale analysis (n=5, mean ± SEM) was used to compare the uptake of MC-LR in (B) rtOatp1d1 and (C) human OATP1B3- transfected HEK293 cells, after subtracting greyscale signals for ev-HEK293 cells or non-transfected HEK293 cells respectively.