EPO suppresses hepcidin indirectly by inducing erythropoiesis. Reticulocyte fractions (A), serum iron (B), and hepcidin mRNA (C) were determined after each indicated treatment and compared by rank sum test to “no EPO” (*P < .005, ^#P = .01, ^%P < .05) or compared by rank sum test to “EPO” (^&P ≤ .002). Hepcidin mRNA was normalized to actin mRNA and ratios to “no EPO” are shown. Error bars indicate one standard deviation.