Altered cellular distribution of iron in rat cerebral cortex during the oestrous cycle

Iron levels in blood, liver and the substantia nigra fluctuate during the oestrous cycle but it is not known whether the cellular distribution also changes. This study shows that during dioestrus, when serum levels of oestradiol are low, the amount of histochemically detectable iron in the cerebral cortex is significantly lower than in proestrus when oestradiol levels are highest. During dioestrus iron is concentrated within neurones, and the transition to proestrus is associated with a shift in iron localisation from neurones to vascular endothelial cells and oligodendrocytes. These data raise the possibility that changes in the concentration of serum oestrogen (or other reproductive hormones) during the oestrous cycle can influence the intercellular transport of iron in the brain.