Acylation of lyso platelet-activating factor by splenocytes of the rainbow trout, Oncorhyncus mykiss.
In mammalian systems, platelet-activating factor, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine, (PAF) is rapidly inactivated by a deacetylation/reacylation system that produces 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine which is highly enriched in arachidonic acid. There is some evidence that n-3 fatty acids may have an impact on this system in humans but the nature of this impact is unclear. In rainbow trout, n-3 fatty acids are known to be essential dietary components which are derived through the food chain. Substantial quantities of n-3 fatty acids are found in trout membrane phospholipids. We show here that in sharp contrast to mammalian cells, trout cells acylate lyso platelet-activating factor, alkyl-GPC, 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine, (lyso-PAF) with a high degree of specificity for n-3 fatty acids. When [3H]lysoPAF was incubated with these cells, only three molecular species of alkylacylglycerophosphocholine were produced, and 92% contained n-3 fatty acids. Since isolated membranes yielded similar results, it appears that the acylation proceeds via a coenzyme A-independent transacylase as found in mammalian systems.
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Mountain Aquaculture Research Center, Western Carolina University, Cullowhee, North Carolina 28723.
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Turner
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Lumb
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D000215:Acylation; D000818:Animals; D003065:Coenzyme A / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000096:biosynthesis; D066298:In Vitro Techniques; D010972:Platelet Activating Factor / Q000031:analogs & derivatives* / Q000378:metabolism; D013154:Spleen / Q000378:metabolism; D014337:Trout / Q000378:metabolism*
D015525:Fatty Acids, Omega-3; C029271:O-deacetyl platelet activating factor; D010972:Platelet Activating Factor; D003065:Coenzyme A