Furthermore, hepcidin and the iron regulatory proteins 1 and 2 (IRP1 and IRP2) as well as aconitase activity (that reflects amount of IRP1 protein containing 4S-4Fe cluster and thus deprived of IRE binding capacity), jointly responsible for the regulation of expression of iron handling proteins, were unchanged in HF rats (Fig. 4E–H). The gene discussed is IREB2; the disease is hydrops fetalis.