This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Dayuan Li Articles by Mehta, J. L. Search for Related Content PubMed Articles by Dayuan Li, Articles by Mehta, J. L. Social Bookmarking                         What's this?

Relative Effects of - and -Tocopherol on Low-Density Lipoprotein Oxidation and Superoxide Dismutase and Nitric Oxide Synthase Activity and Protein Expression in Rats

Department of Medicine, University of Florida, and VA Medical Center, Gainesville, Florida

Tom Saldeen

Department of Forensic Medicine, University of Uppsala, Uppsala, Sweden

Francesco Romeo

Department of Cardiology, University of Catania, Italy

Jawahar L. Mehta

Department of Medicine, University of Florida, and VA Medical Center, Gainesville, Florida

Background: Increasing evidence suggests that vitamin E prevents the progression of ath erosclerosis by inhibiting platelet aggregation, monocyte adhesion. and improving plaque stability and vasomotor function. Recently, controversy has arisen as to the relative effects of - and -tocopherol in modulating some mediators of atherosclerosis.

Methods and Results: We examined the effects of - and -tocopherol on constitutive nitric oxide synthase (cNOS) and superoxide dismutase (SOD) activity and protein expression in rats. Sprague-Dawley rats were fed regular chow or chow mixed with - or -tocopherol (100 mg/kg/ day) for 7 to 10 days. Plasma - and -tocopherol levels, low-density lipoprotein (LDL) oxida tion, and cNOS and SOD activity and protein expression were measured. Plasma -tocopherol levels were significantly increased (P < .01 vs control), but -tocopherol levels fell (P < .01 vs control) in rats fed -tocopherol. Plasma -tocopherol levels were increased (P < .01 vs con trol), and -tocopherol levels did not change in rats fed -tocopherol. Both - and -tocopherol feeding decreased the rate of LDL oxidation induced by phorbol 12-myristate 13-acetate (PMA)-stimulated leukocytes (P < .01 vs control). Both - and -tocopherol increased SOD activity in plasma and arterial tissues as well as Mn SOD and Cu/Zn SOD protein expression in arterial tissues (all P < .01 vs control). -Tocopherol was more potent than -tocopherol in all these effects (P < .05). Both a- and -tocopherol increased NO generation and cNOS activity (all P < .05 vs control). However, only -tocopherol increased cNOS protein expression.

Conclusions: These observations indicate that whereas both - and -tocopherol exert important effects on determinants of oxidation and vasomotor function, effects of dietary -tocopherol supplementation in vivo are less pronounced than those of -tocopherol supplementation.

Key Words: vitamin E • nitric oxide synthase • superoxide dismutase.

Journal of Cardiovascular Pharmacology and Therapeutics, Vol. 4, No. 4, 219-226 (1999)
DOI: 10.1177/107424849900400403


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?