| Research Abstract |
In this study, tissue lipid peroxide formation after ingestion of n-3 polyunsaturated fatty acids, primarily docosahexaenoic acid, was investigated in relation to lipid peroxide scavengers and fatty acid compositions of total lipids, neutral lipids and phosholipids in some tissues. As a result, the lipid peroxide levels produced in tissues such as liver, kidney, brain and testis in response to increasing levels of dietary DHA were not as high as expected from the peroxidizability indexes which were calculated from the fatty acid compositions of tissue total lipids. No tissue injuries were also observed concurrently. The reasons to suppress under the peroxidizability index were presumed as follows. 1) The levels of water-soluble antioxidants such as ascorbic acid and glutathione were increased, leading to stimulation of reductive regeneration of tocopherols from tocopheroxyl radicals. 2) Incorportation of n-3 polyunsaturated fatty acids, especially DHA, into tissues differed from tissue to tissue, and the tissue low in DHA formed less lipid peroxides. 3) DHA was preferentially utilized for phosphatidylethanolamine (PE) synthesis and the antioxidative stability of PE was thought to be potentiated by coexistence with VE. 4) Conformational changes of phospholipids which bind DHA may lead to a stabilized form, and thus, it may augment stability against oxidation resultantly. 5) Peroxisomal β-oxidation stimulates metabolic degradation of DHA vulnerable to oxidation.
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