Glutathione release and catabolism during energy substrate restriction in astrocytes

Brain Research
B H JuurlinkL Hertz

Abstract

This study examined the effect of simulated ischemia (deprivation of both oxygen and substrate) on astrocyte reduced-glutathione (GSH). We have demonstrated that under normoxic conditions there is no GSH efflux from living astrocytes; this suggests that the high levels of GSH in astrocytes in vivo are not available for neighbouring neural cells. Under simulated ischemia there is release of GSH from astrocytes only when astrocytes die. Furthermore, when astrocytic energy stores are depleted GSH is catabolized, such that after 12 h of simulated ischemia approximately 20% of GSH is catabolized. This GSH catabolism can be increased at an earlier time by causing increased ATP utilization through activating the sodium pump either by introducing glutamate into the culture medium or by raising medium potassium. Since GSH is catabolized into glycine, glutamate and cysteine, the latter two amino acids being neurotoxic, our findings indicate that the high levels of GSH in astrocytes may be used by these cells to survive ischemic insults, but the catabolism of GSH may result in increased neuronal damage.

Citations

May 20, 2003·Biological Chemistry·Ralf Dringen, Johannes Hirrlinger
Apr 23, 2005·Glia·Gerald A Dienel, Leif Hertz
Jan 1, 1999·Neuropathology : Official Journal of the Japanese Society of Neuropathology·Y Nomura
Dec 13, 2017·British Poultry Science·M BatorynaG Formicki
Oct 20, 2000·Analytical Biochemistry·H KamencicB H Juurlink
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Jan 17, 2009·Journal of the Neurological Sciences·Arundhati JanaKalipada Pahan

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