An autoradiographic study of the uptake and distribution of iron by the brain of the young rat.

Rats aged 15, 28, or 42 days were injected intraperitoneally with iron-59 and were sacrificed at varying intervals. Total acquisition of iron-59 by the brain, when compared to levels of iron-59 in blood sampled 48 h after injection, diminished with increasing age at injection. Cerebral levels of iron-59 in animals injected at age 15 days did not change with postinjection interval despite rapidly decreasing serum levels of iron-59. Thus, iron acquired by the brain early in postnatal development becomes sequestered in that organ. However, autoradiography of the brains of animals injected at age 15 days showed definite changes over time in the anatomic distribution of the isotope. This suggests that mechanisms may exist for the translocation of iron from one area of the brain to another.