Enhanced erythropoietic recovery and Epo/EpoR signaling after erythropoietic stress in Lnk-deficient mice. Wild-type and Lnk-deficient mice were injected with phenylhydrazine (PHZ) at days 0 and 1 (indicated by arrows). Hematocrits (A) and reticulocyte counts (B) were measured at indicated intervals (mean ± standard deviation [SD]). The corrected reticulocyte count (also known as reticulocyte index) was calculated assuming a normal hematocrit of 45%, as follows: corrected reticulocyte count (%) = reticulocyte count (%) × (hematocrit/45). There were 8 to 9 mice used in 2 independent studies. Student t tests were performed and P values are shown on top of each pair of data points. (C) At days 4 and 5 after PHZ treatment, spleen cells were isolated. CD71⁺ populations were purified using magnetic beads, and stimulated with 0, 1, 10, or 100 U/mL Epo for 10 minutes. Protein lysates from equal cell numbers were subjected to Western blotting analysis. Phosphorylated and total protein levels of p42/44MAPK and Akt are shown. Results shown here are representatives of 3 independent experiments, and 3 wild-type and 3 Lnk-deficient mice were used and pooled in each experiment.