Hepcidin-22

Where it comes from

Made in

Cut from hepcidin-25 in blood and kidney

Sent out by

Rises with kidney failure and inflammation

Acts on

• Ferroportin (weakly)

What it does

• Little effect on iron: the first residues that hepcidin-25 needs to bind and destroy ferroportin are the ones it has lost ¹
• Interferes with older hepcidin assays, which could not tell the forms apart and so read the total as if it were all active ²
• May keep some antimicrobial activity, which is what the hepcidins were first found doing

In medicine

• No use of its own. Its existence is the reason a clinical hepcidin assay has to be specific for hepcidin-25 ²
• It is one of three forms found together in human serum, and the proportions shift with kidney function and inflammation rather than with iron ¹

Beyond the body’s own use

• Not studied as a treatment, and no analogue of it has been made: a weaker hepcidin is of no obvious use, since the medicines in this family are built to act more strongly, not less
• What is unsettled is where the trimming happens and whether it is regulated. If the body cuts hepcidin-25 deliberately, that would be a way of switching the hormone off, and nobody has shown it either way ¹