The effect of the hepcidin-ferroportin interaction on cellular iron export. When hepcidin concentrations are low, cellular iron is exported into plasma through membrane-associated ferroportin (Fpn). When hepcidin concentrations are high, hepcidin binds to ferroportin, and ferroportin is internalized and degraded. As a consequence of the loss of ferroportin, cellular iron export decreases and iron accumulates in cytoplasmic ferritin.