Glial metallothionein.

The metal-binding protein, metallothionein (MT) has been found to be primarily produced by astrocytes in the rat and human brain. This review discusses the relationship of glial MT to the distribution of metals in the brain, possible roles of MT in the regulation of glial enzymes and other glial proteins, and the possible role of a subset of MT-immunoreactive glia, the Gomori-positive astrocytes, in defending against toxic metals that enter the brain via circumventricular organs. The possible involvement of MT-containing astrocytes in degenerative brain disorders in also briefly discussed.