The role of the metals copper, zinc, magnesium, lead, manganese,
mercury, lithium and aluminium in neuropsychiatric disease are well
known and has been discussed on several occasions. Yet little attention
has been paid to iron, the most abundant transitional metal in the body
and the earth's crust. Iron plays a major role as a cofactor of numerous
metabolic enzymes, it is important for DNA and protein synthesis, and
has a crucial role in the oxygen carrying capacity of haemoglobin. Some
of the most devastating diseases of systemic organs are associated with
abnormal iron metabolism. Yet only very recently its role in the central
nervous system has been considered. Thus nutritional iron defi- ciency
and iron overload afflict some 500-600 million people. It is also well
recognized that too little or too much iron can produce profound effects
on the metabolic state of the cell, and therefore the regulation of iron
uptake and disposition is tightly relegated by the cell. Its transport
into the cell and storage are handled by transferrin, ferritin and
haemo- siderin. Nowhere are these processes so well recognized as in the
case of brain iron metabolism. Iron does not have ready access to the
adult brain as it does to other tissues, since it does not cross the
blood brain barrier (BBB). All the iron present in brain is deposited
before the closure of BBB at an early age where it is sequestered and
conserved. Therefore its turnover is extremely slow.
