Thrombin and S1P up-regulate EDG-1 and -3 mRNA and protein expression. ECs were treated with or without 10 nM thrombin and 4 μM S1P for 30 minutes (A) and 3 hours (B). The cells were then harvested and processed for determination of EDG-1 and -3 mRNA and protein level by quantitative RT-PCR (A) and by Western blot analysis (B), respectively. As control, GAPDH was also analyzed by quantitative RT-PCR (A). Similar results were observed in 2 independent experiments.