Increase in hemoglobin synthesis by EPO and TPO, and suppression by GM-CSF in UT-7/GM cells. UT-7/GM cells were cultured in tissue culture flasks with GM-CSF (10 ng/mL), EPO (10 U/mL), TPO (100 ng/mL), or their combinations. Two weeks later, the cells cultured under various conditions were obtained and stained with dianisidine as described in Materials and Methods.