EFFECTS OF DIET AND DEVELOPMENT UPON THE UPTAKE AND DISTRIBUTION OF CEREBRAL IRON

In order to determine whether iron sequestered by the rat brain during the third week of postnatal life could be mobilized by subsequent die tary iron deficiency (ID), iron-59 (Fe-59) was administered to rats at 2 weeks of age. The animals were placed on an ID or a control diet fr om age 4 through 8 weeks and killed by perfusion. Brain radioactivity was identical for both groups, and autoradiography revealed no differe nces in the distribution of radioactivity. Thus, neither the sequestra tion of cerebral iron acquired at age 2 weeks nor its subsequent redis tribution was affected by ID. Since ID beginning after age 3 weeks rep ortedly produces a cerebral iron deficit that is in part reversible, a n attempt was made to determine whether Fe-59 administered after ID wa s preferentially delivered to any brain region. Rats were placed on an ID or a control diet from age 3 through 7 weeks and then injected wit h Fe-59, placed on a normal diet, and killed 2 weeks later. Thre was n o difference between groups in amount or distribution of brain Fe-59, except in the choroid plexus, which was more radioactive in the ID rat s than in the controls. This finding may represent a mechanism by whic h the choroid plexus buffers the brain against rapid rises in plasma i ron content.