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. Author manuscript; available in PMC: 2009 Nov 20.
Published in final edited form as: Mol Pharmacol. 2007 Oct 24;73(1):243–251. doi: 10.1124/mol.107.039594

Fig. 2.

Fig. 2

Effects of mrp4 deficiency on the intracellular accumulation of PMEA and cyclic AMP in MEF cells. A and B, cytotoxicities of PMEA and vinblastin. Mrp4+/+ and mrp4−/− MEF cells were exposed to various concentrations of PMEA or vinblastine for 72 h. Cell viability was then determined by the MTS cytotoxicity assay and expressed as a percentage of a vehicle-treated control. Data points are the mean ± S.E. of three determinations. C, extracellular and intracellular levels of cAMP. After 24 h of culture under normal conditions, mrp4+/+ and mrp4−/− MEF cells were treated with vehicle or 10 μM FSK for 1 h. The growth medium and cellular extracts were collected and assayed for cAMP levels using an EIA kit as described under Materials and Methods. Both extracellular and intracellular levels of cAMP were normalized against the amount of intracellular protein for respective samples and expressed as picomoles per milligram of protein. Values are the mean ± S.E. of three determinations. Statistical difference was determined by a one-way ANOVA. *, p < 0.05, compared with the control in each genotype. **, p < 0.05, compared with control mrp4+/+ MEF cells. #, p < 0.05, compared with FSK-treated mrp4+/+ MEF cells.