AJP - Cell Physiology, Vol 267, Issue 1 C177-C188, Copyright © 1994 by American Physiological Society

ARTICLES

Cell fatty acid composition affects free radical formation during lipid peroxidation

J. A. North, A. A. Spector and G. R. Buettner
Department of Biochemistry, College of Medicine, University of Iowa, Iowa City 52242.

Lipid-derived free radicals generated from intact human U937 monocytes exposed to iron-induced oxidative stress were detected by electron paramagnetic resonance (EPR) with the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN). Lipid radical formation was enhanced when the cells were enriched with n-3 or n-6 polyunsaturated fatty acids. Computer simulation indicated that at least two POBN spin adducts were formed, having spectral characteristics consistent with carbon-centered radicals (aN = 15.9 G and aH = 2.6 G; aN = 15.1 G and aH = 2.8 G). These alkyl radicals are probably formed by beta-scission of alkoxyl radicals. POBN spin adduct formation correlated with ethane generation. Addition of ascorbate to the assay medium greatly increased the radical signal intensity. Although radical generation was cell dependent and POBN spin adducts were observed in cell homogenates, the adducts formed by the intact cells were detected only in the extracellular medium. These findings indicate that the extent of lipid radical formation in response to oxidative stress can be influenced by changes in the polyunsaturated fatty acid composition of the cell lipids and suggest the possibility that carbon-centered lipi radicals may interact with extracellular structures.

This article has been cited by other articles:

				J. Bjorkegren, A. Beigneux, M. O. Bergo, J. J. Maher, and S. G. Young Blocking the Secretion of Hepatic Very Low Density Lipoproteins Renders the Liver More Susceptible to Toxin-induced Injury J. Biol. Chem., February 8, 2002; 277(7): 5476 - 5483. [Abstract] [Full Text] [PDF]

				D. E. Williard, S. D. Harmon, T. L. Kaduce, M. Preuss, S. A. Moore, M. E. C. Robbins, and A. A. Spector Docosahexaenoic acid synthesis from n-3 polyunsaturated fatty acids in differentiated rat brain astrocytes J. Lipid Res., September 1, 2001; 42(9): 1368 - 1376. [Abstract] [Full Text] [PDF]

				R. C Wander and S.-H. Du Oxidation of plasma proteins is not increased after supplementation with eicosapentaenoic and docosahexaenoic acids Am. J. Clinical Nutrition, September 1, 2000; 72(3): 731 - 737. [Abstract] [Full Text] [PDF]

				R. Pamplona, M. Portero-Otín, D. Riba, J. R. Requena, S. R. Thorpe, M. López-Torres, and G. Barja Low Fatty Acid Unsaturation: A Mechanism for Lowered Lipoperoxidative Modification of Tissue Proteins in Mammalian Species With Long Life Spans J. Gerontol. A Biol. Sci. Med. Sci., June 1, 2000; 55(6): 286B - 291. [Abstract] [Full Text]

				L. N. Kolonel, A. M. Y. Nomura, and R. V. Cooney Dietary Fat and Prostate Cancer: Current Status J Natl Cancer Inst, March 3, 1999; 91(5): 414 - 428. [Abstract] [Full Text] [PDF]

				R. Pamplona, M. Portero-Otín, D. Riba, C. Ruiz, J. Prat, M. J. Bellmunt, and G. Barja Mitochondrial membrane peroxidizability index is inversely related to maximum life span in mammals J. Lipid Res., October 1, 1998; 39(10): 1989 - 1994. [Abstract] [Full Text]

				A. W. Girotti Lipid hydroperoxide generation, turnover, and effector action in biological systems J. Lipid Res., August 1, 1998; 39(8): 1529 - 1542. [Abstract] [Full Text]

				I. R. Brude, C. A. Drevon, I. Hjermann, I. Seljeflot, S. Lund-Katz, K. Saarem, B. Sandstad, K. Solvoll, B. Halvorsen, H. Arnesen, et al. Peroxidation of LDL From Combined-Hyperlipidemic Male Smokers Supplied With ¯-3 Fatty Acids and Antioxidants Arterioscler. Thromb. Vasc. Biol., November 1, 1997; 17(11): 2576 - 2588. [Abstract] [Full Text]

				M. L. Tiku, R. Shah, and G. T. Allison Evidence Linking Chondrocyte Lipid Peroxidation to Cartilage Matrix Protein Degradation. POSSIBLE ROLE IN CARTILAGE AGING AND THE PATHOGENESIS OF OSTEOARTHRITIS J. Biol. Chem., June 23, 2000; 275(26): 20069 - 20076. [Abstract] [Full Text] [PDF]