Intracellular translocation of glutathione S-transferase pi during oligodendrocyte differentiation in adult rat cerebral cortex in vivo

Glutathione S-transferase (GST)-pi is a cytosolic isoenzyme used as a marker for mature oligodendrocytes in the mammalian brain. However, the cellular properties of GST-pi-immunoreactive [GST-pi (+)] cells in adult brain are not completely understood. We immunohistochemically demonstrated the existence of two subtypes of GST-pi (+) cells in the cerebral cortex of adult rats: one subtype exhibited GST-pi in the cytoplasm (C-type cells), while the other did mainly in the nucleus (N-type cells). The GST-pi (+) C-type cells were also immunopositive for 2′,3′-cyclic nucleotide 3′-phosphodiesterase and RIP, indicating that they were mature oligodendrocytes, while the GST-pi (+) N-type cells expressed NG2, indicating that they were oligodendrocyte progenitor cells. Furthermore, observation of the fate of newly-generated cells by 5-bromodeoxyuridine-labeling revealed that the GST-pi (+) N-type cells differentiated into C-type cells. These findings indicate translocation of GST-pi from the nucleus to the cytoplasm during oligodendrocyte maturation.