Hepcidin is a peptide hormone produced by the liver discovered in 2000, that appears to be the master regulator of iron homeostasis in humans and other mammals. In humans, HAMP is the gene that encodes for hepcidin.
Hepcidin preprohormone, prohormone and hormone size are 84, 60 and 25 amino acids respectively. 20 and 22 amino acid forms of Hepcidin also exist in the urine. The N terminal region is required for function, and deletion of 5 N-terminal peptides results in a loss of function. Hepcidin has a beta-sheet rich structure with 4 disulfide bonds. Hepcidin directly inhibits ferroportin, a protein that transports iron out of cells that store it. This prevents enterocytes of the intestines from secreting iron into the hepatic portal system, reducing iron absorption.