Iron enters enterocyte by :
(A) Divalent cation transpoer (B) Ferropoin (C) Hephaestin (D) Ceruloplasmin
(A) *.Cytochrome b reductase 1 or Duodenal cytochrome b (Dcytb) is a ferric reductase enzyme conves Fe3+ to Fe2+, and aid the entry of Fe2+ into the mucosal cell *The ferrous iron is then transpoed in the cell by a divalent metal transpoer (DMT-1). *Ferropoin and Hephaestin proteins are at the basolateral membrane and helps in transpo of iron from intestine cell to plasma. Divalent Metal/Cation Transpoer 1(DMT1 or DCT1) /Natural resistance-associated macrophage protein 2(NRAMP 2) *Located on the apical membrane of enterocytes * Transpo of ferrous iron * DMT1 expression is regulated by body iron stores to maintain iron homeostasis. Hephaestin, also known as HEPH * Transmembrane protein, *Homology with ceruloplasmin * Involved in the metabolism and homeostasis of iron * Mainly involved in iron efflux at the basolateral membrane, in association with ferropoin. * The highest expression of hephaestin is found in small intestine.