Staats D A, Colby H D
Department of Pharmacology and Toxicology, Philadelphia College of Pharmacy & Science, PA 19104.
J Steroid Biochem. 1989 Apr;32(4):609-11. doi: 10.1016/0022-4731(89)90396-8.
Studies were done to evaluate the role of alpha-tocopherol in modulating the effects of ascorbic acid (AA) on lipid peroxidation (LP) by adrenocortical mitochondria. In control mitochondria from the inner (zona reticularis) or outer (zona fasciculata plus zona glomerulosa) zones of the guinea pig adrenal cortex, subphysiological concentrations of AA stimulated LP but higher levels had little or no effect. However, after depletion of adrenal tocopherol, even physiological concentrations of AA exerted prooxidant effects, stimulating LP. To assess the antioxidant potency of AA, its effects to inhibit ferrous ion (Fe2+)-induced LP were determined. Mitochondria from the outer zone contained far more alpha-tocopherol than those from the inner zone and were more sensitive to the antioxidant effects of AA. After tocopherol depletion, the antioxidant potency of AA in outer zone mitochondria decreased, but there was little change in the inner zone. The results indicate that the actions of AA are determined in part by mitochondrial tocopherol content, and, as a result, vary in the different zones of the adrenal cortex.
开展了多项研究，以评估α-生育酚在调节抗坏血酸（AA）对肾上腺皮质线粒体脂质过氧化（LP）作用方面的角色。在豚鼠肾上腺皮质内层（网状带）或外层（束状带加球状带）区域的对照线粒体中，亚生理浓度的AA会刺激LP，但较高水平的AA几乎没有影响。然而，在肾上腺生育酚耗尽后，即使是生理浓度的AA也会发挥促氧化作用，刺激LP。为评估AA的抗氧化能力，测定了其抑制亚铁离子（Fe2+）诱导的LP的作用。外层区域的线粒体所含的α-生育酚远比内层区域的线粒体多，并且对AA的抗氧化作用更敏感。生育酚耗尽后，外层区域线粒体中AA的抗氧化能力下降，但内层区域几乎没有变化。结果表明，AA的作用部分取决于线粒体生育酚含量，因此，在肾上腺皮质的不同区域有所不同。
