IRON UTILISATION IN THE BODY

Iron leaving the enterocytes, following absoption, is transported in the blood bound to the 80 kDa transport molecule transferrin. This molecule can carry two Fe⁺⁺⁺ ions and can in theory supply every cell of the body with iron. Particularly the immature erythrocyte precursors (reticulocytes) of the bone marrow are important target cells for transferrin bound iron.

The transferrin/iron complex can undergo endocytosis after binding to a transferrin receptor on the target cell surface. After being acidified by lysosomes the iron fraction of the internalised endosome is liberated and the transferrin and its receptor is brought back via the cell surface to the blood.

(Iron can probably also be brought into the target cell via other mechanisms.)

Iron distribution in the body [Ref 1]

[Ref 3]

Functional tissue iron - see Appendix.