Antioxidants reduce peroxyl-mediated inhibition of mitochondrial transcription.
We have recently shown that the mitochondrial transcription system is extremely sensitive to inhibition by peroxyl radicals generated by either 2,2'-azobis(2-amidinopropane) (AAPH) or 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN), and that this inhibition occurs prior to detectable evidence of lipid peroxidation as measured by thiobarbituric acid (TBA)-reactive substances, 4-hydroxynonenal accumulation, and oxygen consumption. In this report, we further confirm that mitochondrial transcription is sensitive to oxidative stress. We also demonstrate that alpha-tocopherol, ascorbate, and glutathione can partially attenuate these effects, but none of the three, nor the three together, are capable of completely preventing this oxidant-induced repression. This suggests that these physiological antioxidants, while capable of preventing lipid peroxidation chain reactions, are less effective at protecting the mitochondrial transcriptional machinery against this oxidative insult.
Department of Physiology, University of Texas Health Science Center, San Antonio 78284-7756.
B S
BS
Kristal
B J
BJ
Park
B P
BP
Yu
D000578:Amidines / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology; D001391:Azo Compounds / Q000378:metabolism; D005978:Glutathione / Q000494:pharmacology; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D009570:Nitriles / Q000378:metabolism; D010545:Peroxides / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D014158:Transcription, Genetic / Q000187:drug effects*; D014810:Vitamin E / Q000494:pharmacology
D000578:Amidines; D000975:Antioxidants; D001391:Azo Compounds; D009570:Nitriles; D010545:Peroxides; C055792:2,2'-azobis(2,4-dimethylvaleronitrile); D014810:Vitamin E; C049375:perhydroxyl radical; C046728:2,2'-azobis(2-amidinopropane); D005978:Glutathione; D001205:Ascorbic Acid