BRAIN UPTAKE OF TRACE-METALS, ZINC AND MANGANESE, IN RATS

The brains of rats injected intravenously with (ZnCl2)-Zn-65 or (MnCl2 )-Mn-54 were subjected to high resolution autoradiography. Zn-65 and M n-54 were largely concentrated in choroid plexus 1 h after injection a nd then gradually decreased, with increases in other brain regions, su ggesting that both metals were taken up gradually into brain mainly vi a cerebrospinal fluid in the choroid plexus. By 3 days after injection , relatively high level of Zn-65 was seen in the dentate gyrus and CA3 region of the hippocampus and in the cerebral cortex. The level of Mn -54 was also high in the former, while relatively low in the latter.