Induction of glutamine synthetase by L-alpha-aminoadipate in developmental stages of cultured astrocytes.

摘要

Effect of L-alpha-aminoadipate (L alpha AA), a gliotoxic L-glutamate analogue, on glutamine synthetase (GS) activity of rat cultured astrocytes was examined, L alpha AA at sub-toxic concentrations (less than 0.5 mM, for 48 h) increased GS activity of cultured astrocytes. This increase was prevented by 10 microM cycloheximide, an inhibitor of protein synthesis. L alpha AA increased GS activities of astrocytes cultured in three different conditions, i.e. 12-day-old, 5-233k-old and dibutyryl cAMP(DBcAMP)-induced differentiated cultures. Insulin (10 micrograms/ml) and hydrocortisone (10 microM) increased GS activity of 12-day-old cultured cells, but not that of 5-weeks-old and DBcAMP-treated cells. The increase in GS activity was observed after a transient treatment with L alpha AA for 4 h. These results show that the induction of GS by L alpha AA is not related to developmental stages of astrocytes in culture.