d-α-Tocopherol, but not d-β-tocopherol, negatively regulates proliferation of vascular smooth muscle cells at physiological concentrations. d-α-Tocopherol inhibits protein kinase C (PKC) activity, whereas d-β-tocopherol is ineffective. Furthermore d-β-tocopherol prevents the inhibition of cell growth and of PKC activity caused by d-α-tocopherol. The negative regulation by d-α-tocopherol of PKC activity appears to be the cause and not the effect of smooth muscle cell growth inhibition. d-α-Tocopherol does not act by binding to PKC directly but presumably by preventing PKC activation. It is concluded that, in vascular smooth muscle cells, d-α-tocopherol acts specifically through a nonantioxidant mechanism and exerts a negative control on a signal transduction pathway regulating cell proliferation.
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - Dec 19 1995|
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