Li R K, Cowan D B, Mickle D A, Weisel R D, Burton G W
Department of Clinical Biochemistry, Toronto Hospital, Ontario, Canada.
Free Radic Biol Med. 1996;21(4):419-26. doi: 10.1016/0891-5849(96)00034-2.
To determine the effect of vitamin E on cellular antioxidant enzymes, human ventricular cardiomyocytes were incubated with 200 microM all-racemic-alpha-tocopheryl acetate for 14 d at pO2s of 150 and 40 mm Hg. Cellular Cu, Zn superoxide dismutase, catalase, and GSH-Px1 activities were measured. Although SOD and catalase activities were unaffected by alpha-tocopherol, GSH-Px1 activities increased (p < .0001) as much as twofold. This increase was independent of oxygen tension and selenium. The increase in GSH-Px1 activity became significant (p < .01) by day 4. A nonantioxidant analog of alpha-tocopherol, 200 microM RRR-alpha-tocopherol methyl ether, did not affect GSH-Px1 activities. Although GSH-Px1 mRNA levels mirrored the changes in enzyme activities, the de novo nuclear GSH-Px1 transcript synthesis was unaffected by alpha-tocopherol. Because the increase in GSH-Px1 activities also occurred after cellular alpha-tocopherol levels had plateaued, the above results were most consistent with posttranscriptional stabilization of GSH-Px1 mRNA by alpha-tocopherol or an alpha-tocopherol-related metabolic product.
为了确定维生素E对细胞抗氧化酶的影响，将人心室心肌细胞与200微摩尔全消旋α-生育酚醋酸酯在150和40毫米汞柱的氧分压下孵育14天。测量细胞铜、锌超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶1（GSH-Px1）的活性。尽管超氧化物歧化酶和过氧化氢酶的活性不受α-生育酚的影响，但GSH-Px1的活性增加了（p <.0001），高达两倍。这种增加与氧张力和硒无关。到第4天，GSH-Px1活性的增加变得显著（p <.01）。α-生育酚的一种非抗氧化类似物，200微摩尔RRR-α-生育酚甲醚，不影响GSH-Px1的活性。尽管GSH-Px1 mRNA水平反映了酶活性的变化，但α-生育酚不影响GSH-Px1从头合成的核转录本。由于在细胞α-生育酚水平达到平稳后GSH-Px1活性也出现增加，上述结果最符合α-生育酚或与α-生育酚相关的代谢产物对GSH-Px1 mRNA的转录后稳定作用。
