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Phospholipid And Triglyceride Content Of -linolenic, Eicosapentaenoic, Docosapentaenoic And Docosahexaenoic Acid In The Liver Of Normal And 3-fatty Acid Depleted Rats: Comparison With Corresponding Plasma Values

Willy J.Malaisse, Yvon A.Carpentier, Laurence Portois

Alterations of desaturase- and elongase-catalyzed steady-state equilibrium between selected fatty acids were recently documented in liver phospholipids and triglycerides of 3 fatty acid-depleted rats. In the present study the ratio between -linolenic, eicosapentaenoic, docosapentaenoic and docosahexaenoic acid was measured in liver phospholipids and triglycerides, as well as plasma phospholipids, triglycerides and unesterified fatty acids of normal and 3-depleted rats. Unexpectedly, the C22:53/C22:63 ratio was virtually identical in the hepatic phospholipids of normal and 3-depleted rats injected intravenously with saline one hour before liver sampling. Also unexpectedly, the same ratio in plasma phospholipids was about four times higher in the saline-injected 3-depleted rats than in the salineinjected normal rats. It is proposed that the latter anomaly indicates a perturbation, in the 3-depleted rats, of the hierarchy between distinct long-chain polyunsaturated 3-fatty acids in terms of their release from circulating glycerides and further clearance from the bloodstream. Such a proposal was supported by comparing the relative abundance of the different 3-fatty acids in the plasma phospholipids or triglycerides and plasma unesterified fatty acids of normal and 3-depleted rats injected one hour before liver and blood sampling with a medium-chain triglyceride:fish oil emulsion, which provokes a rapid increase in the C20:53, C22:53 and C22:63 content of liver phospholipids and triglycerides.