Analysis of synthetic hepcidin by 12.5% acid-urea polyacrylamide gel electrophoresis (PAGE). The gel was loaded with the indicated amounts of peptide and after electrophoresis it was stained with Coomassie blue. The standard is 1 μg hepcidin produced synthetically and validated as identical to urinary hepcidin-25 by mass spectrometry, reverse-phase high-performance liquid chromatography on a C18 column, and acid-urea PAGE (courtesy of E. Nemeth and T. Ganz, University of California, Los Angeles).