Treatment with rhEpo increases ferroportin expression in skeletal muscle. The figure shows the changes in ferroportin (fpn) expression in muscle biopsy samples obtained from the vastus lateralis before and after 8 and 28 days of rhEpo treatment. (A) Ferroportin mRNA levels were normalized to total cDNA content and are expressed in relation to the pretreatment value, arbitrarily defined as 100. (B) Experiments confirm antibody specificity by peptide competition: muscle extract from the same biopsy was blotted with anti–ferroportin antibody preincubated in the presence or absence of a molar excess of ferroportin peptide. The similar intensity of the band above 110 kDa indicates equal protein loading. (C) Equal amounts of proteins (as assessed by amido black staining) from muscle biopsy extracts were loaded onto SDS polyacrylamide gels, immunoblotted with antibodies against ferroportin, and visualized by chemiluminescence. The result shown is representative of 3 independent experiments obtained with extracts from 2 participants (#1 and #2). (D) The densitometric quantification of the immunoblot analysis of ferroportin protein content before and after 8 and 28 days of rhEpo treatment. Values are mean ± SE for 8 participants. The statistical differences from pre-rhEpo values were calculated with the Wilcoxon test; *P < .05.