Iron is stored in the liver and RES by ferritin. Two iron binding sites. Made of 24 sub-units. Holds up to 4,500 Fe molecules. Long-term iron storage.
Gene expression is controlled by iron at level of protein translation.
Etiologies in pre-menopausal women include menstruation loses and pregnancy. GI tract is most common site of blood loss in the elderly. Rarer causes include PNH, pulmonary hemosiderosis. Patients after gastrectomy may develop iron deficiency due to impaired iron absorption. Several causes have been postulated for the anemia of chronic disease.