A role of vitamin E in protection against cell injury: Maintenance of intracellular glutathione precursors and biosynthesis

Gary A. PASCOE*, Marc W. FARISS, Kristin OLAFSDOTTIR, Donald J. REED

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

78 Citations (Scopus)

Abstract

The depletion of cell calcium from isolated rat hepatocytes results in stimulated lipid peroxidation, loss of intracellular and mitochondrial GSH (reduced glutathione), and enhancement of both efflux and oxidation of GSH. These events are followed by cell injury and enhance the susceptibility of the cells to toxic chemicals. It is shown herein that an initial event in the generation of such injury is the depletion of cellular α‐tocopherol. α‐Tocopheryl succinate addition (25 μM) to the calcium‐depleted cells markedly elevated the α‐tocopherol content of the cells, inhibited the associated lipid peroxidation, and maintained intracellular GSH levels without affecting its efflux or redox status. This resulted in an enhanced formation of total glutathione after a 5‐h incubation, which correlated with the α‐tocopherol content of the cells, and was greater than that expected by a direct sparing action of vitamin E. Inhibition of hepatocyte glutathione biosynthesis by buthionine sulfoximine (0.5 mM) eliminated the enhancement of GSH formation by vitamin E. Analysis of endogenous and 35S‐labelled prccursors of glutathione biosynthesis by high‐performance liquid chromatography demonstrated that the depletion of cellular α‐tocopherol resulted in the efflux of glutathione precursors. It is concluded that cell injury associated with α‐tocopherol depletion is partly the result of the efflux of glutathione precursors, and hence diminished biosynthesis and intracellular levels of GSH. These losses and resultant cell injury are preventable by maintenance of cellular α‐tocopherol levels.

Original languageEnglish
Pages (from-to)241-247
Number of pages7
JournalEuropean Journal of Biochemistry
Volume166
Issue number1
DOIs
Publication statusPublished - Jul 1987

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