IRON is essential in living organisms:

• chloroplasts (photosynthesis),
• hemoglobin (oxygen transport),
• solutions can be found in the ferrous form (Fe2 +) and ferric (Fe3 +) participating in biochemical reactions.

It is located in the body actively or deposit. In isolation is very toxic, so iron is associated with proteins. Transport is by binding to TRANSFERRIN and the intracellular FERRITIN is shaped.
In iron homeostasis have been more molecules with advances in molecular biology: transferrin receptor 2, divalent metal transporter 1, ferroprotein protein-1, hephaestin, citocomo b duodenal (CITB-D), HEF protein, hemojuvelin and HEPCIDIN.
It was named after CHRISTINA H. PARK, in 2000, in the publication «Hepcidin, a Urinary Atimicrobial Peptide Synthesized in the Liver«, comes from the English «hepatic bactericidal protein», isolated in urine and human plasma.
HEPCIDIN is a peptide, from the HAMP gene (located on chromosome arm 19) is produced in the liver by hepactocitos. Inhibits iron absorption in the duodenum and its release by macrophages in mammals, there is a positive Darwinian selection in the maturation of sequences encoding hepcidin, suggest an adaptive evolution in the evolution of cysteine ​reduction, according to the ecological diversity of mammals.
Mediates hepcidin in the anemia of CHRONIC CONDITIONS: insufficient production of hepcidin by the liver causes hyperabsorption iron from the intestine (iron overload).

Hepcidin antagonists thus can be used to treat anemias and agonists inhibit the production of iron overload.
Hepcidin synthesis may reflect TOTAL BODY IRON CONTENT: a deficit in iron, transferrin saturation is low and the HEF protein (found on the cell surface) attached to the transferrin receptor not transmit no signal to cellular nucellus occurs hepcidin synthesis.