Although the electronic properties of a mineral ion are important in effecting certain metabolic changes, metals are not generally in an ionic state when stored in cells. Thus, when the mineral ion is released from the plasma transport molecule and taken up by the cells composing a tissue or organ, it is complexed to various intracellular ligands that either store the metal or move it to other loci within the cell for usage or, if the metal ion is in excess, they facilitate its elimination.1