Evidence for altered structure and impaired mitochondrial electron transport function in selenium deficiency |
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Authors: | P Rani K Lalitha |
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Institution: | (1) Department of Chemistry, HSB 264, Indian Institute of Technology, 600 036 Madras, India |
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Abstract: | Selenium (Se) deficiency in the experimental models,Coturnix coturnix japonica andCorcyra cephalonica, resulted in impaired mitochondrial substrate oxidations and lowered thiol levels. Studies with respiratory inhibitors confirmed
reduced mitochondrial electron transport enzyme activities, especially at cytochromec oxidase (COX), the terminal segment. Enhanced mitochondrial lipid peroxidation in Se deficiency was more pronounced in the
heart tissue of the quail compared to other tissues. Glutathione peroxidase (GSH-Px) activity toward H2O2 and cumene hydroperoxide were generally low in the insect muscle tissue and activity toward H2O2 was maximal in the quail heart mitochondria that was not very sensitive to Se status. Lowered COX activity in Se deficiency
was more directly correlated with the increased level of lipid peroxidation than with the GSH-Px activity measured, suggestive
of Se mediated protective mechanisms independent of GSH-Px. Electron microscopic observations revealed structural changes
such as loss of cristae with proliferative and degenerative changes of the mitochondria in Se deficiency. Involvement of Se
in maintaining structure and functional efficiency of mitochondria is evident from the present study. |
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Keywords: | Se deficiency mitochondria cytochromec oxidase respiratory enzymes oxidative stress GSH-Px lipid peroxidation Mitochondria structure altered functions substrate oxidation heart and liver insect muscle |
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