Comparison of the antioxidant properties of alpha-tocopherol and alpha-tocopheryl acetate in newborn rabbit lung.
The antioxidant properties of alpha-tocopherol and alpha-tocopheryl acetate in lung tissue were quantitated in vitro by measurement of thiobarbituric acid (TBA) reactants, pentane production and lipid peroxides following either an iron/ascorbate or a xanthine/xanthine oxidase oxidant stress. Lung homogenates were obtained from newborn rabbits treated intravenously with either 10 or 100 mg/kg of either alpha-tocopherol or alpha-tocopheryl acetate. The animals were killed 5 min after dosing to minimize the conversion of alpha-tocopheryl acetate to alpha-tocopherol. Lung homogenates from animals treated with alpha-tocopherol had decreased concentrations of TBA reactants and pentane production after incubation with either oxidant stress compared to lung homogenate from animals treated with alpha-tocopheryl acetate or vehicle alone. Lipid peroxide concentrations were no different in homogenates from alpha-tocopherol or alpha-tocopheryl acetate treated animals. Correlations between antioxidant activity and tissue concentrations of alpha-tocopherol indicate 50% inhibition is achieved with 30-100 micrograms/g lung tissue. In vitro addition of alpha-tocopherol required concentrations between 100 and 200 micrograms/g to reduce lipid peroxidation by 50%.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D000975:Antioxidants; D001205:Ascorbic Acid / Q000494:pharmacology; D007501:Iron / Q000494:pharmacology; D008054:Lipid Peroxides / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D010420:Pentanes / Q000378:metabolism; D011817:Rabbits; D013858:Thiobarbiturates; D024505:Tocopherols; D014810:Vitamin E / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D019820:Xanthine; D014969:Xanthine Oxidase; D014970:Xanthines; D024502:alpha-Tocopherol / Q000031:analogs & derivatives*
D000975:Antioxidants; D008054:Lipid Peroxides; D010420:Pentanes; D013858:Thiobarbiturates; D014970:Xanthines; D014810:Vitamin E; D019820:Xanthine; C033353:pentane; D007501:Iron; D014969:Xanthine Oxidase; D024502:alpha-Tocopherol; C029684:thiobarbituric acid; D001205:Ascorbic Acid; D024505:Tocopherols