Effects of erythropoietin (EPO) treatment (3 times a week [arrows]) on hemoglobin levels, highly fluorescent reticulocytes (% HFR), reticulocyte counts, and trough EPO levels (top to bottom) in subjects undergoing phlebotomy (P) on days 8 and 15.

Young, healthy male volunteers (total n = 30) received bolus infusions of either 500 U/kg of EPO (black squares; n = 10), 100 U/kg of EPO (open triangles; n = 10), or placebo (open circles; n = 10) in a randomized, double-blind trial. Data are presented as mean ± SEM.