IGF-1 induces platelet production and augments platelet activation. (A-B) Flow cytometric analysis of platelet production from MKs induced by IGF-1. CD34⁺ cells were treated with rhTPO for 10 days followed by rhIGF-1 treatment of 4 days. (C-D) Flow cytometric analysis of the activation of culture-derived platelets. Platelets were stimulated with 10 or 100 ng/mL rhIGF-1 for 5 minutes before stimulation with 0.5 μM ADP for 5 minutes, and were then subjected to analysis after CD62p staining. (E) Platelet production from MKs in CD34⁺ cells cultured with 20 ng/mL rhTPO for 10 days and then treated with 100 ng/mL rhIGF-1 with or without 0.5 μM NVP-ADW742, 10 μM U0126 or 20 μM LY294002 for another 4 days. (F) Activation analysis of platelets. Culture-derived platelets were first pretreated with 0.5 μM NVP-ADW742, 10 μM U0126 or 20 μM LY294002 for 20 minutes and were then stimulated with rhIGF-1 for 5 minutes following stimulation with 0.5 μM ADP for 5 minutes. *P < .05, **P < .01, vs the control; ^#P < .05, ^##P < .01, vs the IGF-1-treated group.