Insulin or IGF-1 mimics the proliferative effects of FCS on Ba/F3-WT and Ba/F3-d392 cells. (A) Short-term Epo-dose response assays were performed with Ba/F3-WT (▪,□) and Ba/F3-d392 (▴,▵) cells in SS plus (□,▵) and minus (▪,▴) 10 nmol/L IGF-1. Identical results were obtained with 10 μg/mL insulin. (B) Short-term insulin dose response studies were performed with Ba/F3-WT (▪) and Ba/F3-d392 (▴) cells in SS in the presence of 50 mU/mL Epo. (C ) Short-term IGF-1 dose response studies were performed with Ba/F3-WT (▪) and Ba/F3-d392 (▴) cells in SS in the presence of 50 mU/mL Epo. Data points represent the mean ± SE of triplicate determinations.