Pharmacodynamic effects of chimeric activator variants on reticulocytes, hematocrit, and total platelets in huGYPA transgenic and nontransgenic mice. This figure presents the complete data from Fig. 4, showing all experimental time points. (A) Transgenic mice received a single i.p. injection of darbepoetin, 10F7-EPO variant, or saline at the indicated concentrations (1 pmol darbepoetin = 37 ng; 1 pmol 10F7-EPO variant = 72 ng). Blood samples were obtained by tail-nick on days 0, 4, 7, and 11 postdosing. Measured hematologic parameters were reticulocyte fraction by flow cytometry (B–F) and hematocrit (G–K) and total platelet counts (L–P) by hematology analyzer. Measurements were background-subtracted relative to day 0. Graphs display mean ± SEM (n = 4).