SUBCELLULAR-LOCALIZATION OF ALPHA-TOCOPHEROL AND ITS EFFECT ON RNA-SYNTHESIS IN PERFUSED RABBIT HEART

  • 1 January 1980
    • journal article
    • research article
    • Vol. 29  (3) , 176-184
Abstract
3H-tocopherol was administered by perfusion to rabbit hearts and rapidly entered the myocardial cells with an incorporation rate which was more evident in the .alpha.-tocopherol deficient hearts than in the control hearts. During perfusion, the labeled .alpha.-tocopherol was slightly metabolized and 85% of the radioactivity was recovered as authentic .alpha.-tocopherol. The pattern of .alpha.-tocopherol distribution showed in both perfused hearts a significant binding of the radioactivity to the nuclei. The vitamin was retained with high specific labeling in the mitochondria and in a lower degree in the microsomes and soluble fractions. Small amounts of radioactivity was bound to the myofibrils. Intranuclear distribution of tocopherol revealed that the tocopherol-binding species were acidic nuclear macromolecules, which exhibited characteristics of non-histone chromosomal proteins. Administration of .alpha.-tocopherol exhibited a positive effect on the stimulation of labeled RNA in the tocopherol-deficient perfused hearts. This was particularly evident at the nuclear level. The intracellular distribution of the vitamin and its ability to stimulate RNA synthesis in heart muscle can suggest a possible role of .alpha.-tocopherol in the regulation of gene activity.