title: Dose-dependent modulation of systemic lipid peroxidation and activity of anti-oxidant enzymes by vitamin E in the rat.
abstract: The objective of this work was to examine the time-dependent pro-oxidant versus antioxidant effect of various doses of vitamin E used commonly in experimental studies. Erythrocyte activity of superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT) and plasma lipid peroxidation levels were investigated following biweekly intramuscular administration of 100, 300 and 600 mg/kg of vitamin E at a baseline time point, and additionally at 2, 4 and 6 weeks after initiating treatment. Vitamin E had an antioxidant effect when administered at low doses over short time periods, and increased the activity of antioxidant enzymes. At higher doses and over longer time periods, it increased the level of lipid peroxidation, and attenuated the activity of antioxidant enzymes. These results suggest that time-dependent variations in vitamin E effects should be considered in design and interpretation of experimental antioxidant studies, as well as during clinical trials.
authors.affiliation: Department of Biochemistry, School of Medicine, Medical Sciences/University of Tehran, Tehran, Iran.
authors.forename: Maliheh
authors.initials: M
authors.lastname: Hajiani
authors.forename: Abolfazl
authors.initials: A
authors.lastname: Golestani
authors.forename: Ahmad
authors.initials: A
authors.lastname: Shariftabrizi
authors.forename: Roghieh
authors.initials: R
authors.lastname: Rastegar
authors.forename: Seyedmehdi
authors.initials: S
authors.lastname: Payabvash
authors.forename: Amirali Hassanzadeh
authors.initials: AH
authors.lastname: Salmasi
authors.forename: Ahmad Reza
authors.initials: AR
authors.lastname: Dehpour
authors.forename: Parvin
authors.initials: P
authors.lastname: Pasalar
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005979:Glutathione Peroxidase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism; D014810:Vitamin E / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D014810:Vitamin E; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase