Follistatin-related Gene Protein/FLRG Inhibition of Activin A-induced Hemoglobin Expression and Neutralization by Mouse Follistatin-related Gene Protein/FLRG Antibody. Recombinant Mouse Follistatin-related Gene Protein/FLRG (Catalog # 1255-F3) inhibits Recombinant Human/Mouse/Rat Activin A (Catalog # 338-AC) induced hemoglobin expression in the K562 human chronic myelogenous leukemia cell line in a dose-dependent manner (orange line), as measured by the psuedoperoxidase assay. Inhibition of Recombinant Human/Mouse/Rat Activin A (7.5 ng/mL) activity elicited by Recombinant Mouse Follistatin-related Gene Protein/FLRG (0.1 µg/mL) is neutralized (green line) by increasing concentrations of Goat Anti-Mouse Follistatin-related Gene Protein/FLRG Antigen Affinity-purified Polyclonal Antibody (Catalog # AF1255). The ND50 is typically 3‑12 µg/mL.