Dose effect of compound D-410639 on the tyrosine kinase activities of IGF-1 receptor (panel A), EGF receptor (ErbB1, panel B), and FGF receptor 3 (panel C). Receptor tyrosine kinase activation was compared to the control which received a blank placebo, and the base line control was considered as 100% activity. Error bars indicate standard deviations. Projected EC50 for IGF-1 receptor was 16.9 μM, but the EC50 is not statistically significant. The IC50 for EGF receptor (ErbB1) and FGF receptor 3 are 1.8 μM and 26.5 μM, respectively. See Materials and Methods for detail.