EDITORIALS & PERSPECTIVES Serum hepcidin: a novel diagnostic tool in disorders of iron metabolism

Given its potential toxicity and low bioavailability,iron metabolism in humans is a tightly regulatedprocess. Two main levels of regulation have been described: a cellular regulation that, through the binding of iron-responsive proteins (IRPs) to iron-responsive ele-ments in mRNA from genes encoding proteins of iron metabolism, controls the synthesis of transferrin receptor (necessary for cellular iron procurement) and ferritin (the iron storage protein), and a systemic regulation that mod-ulates intestinal iron absorption and iron mobilization from macrophages and tissue stores. The peptide hor-mone hepcidin, produced by hepatocytes and acting on target cells situated both outside and within the liver, plays a key role in the systemic regulation of iron metab-olism.1 Hepcidin was initially identified as a cysteine-rich uri-nary antimicrobial peptide.2,3 The subsequent observa