Influence of dietary n-3 fatty acids on macrophage glycerophospholipid molecular species and peptidoleukotriene synthesis.
The study examined the ability of dietary n-3 fatty acids to modify mouse peritoneal macrophage glycerophospholipid molecular species and peptidoleukotriene synthesis. After a 2-week feeding period, fish versus corn oil feeding significantly (P less than 0.01) lowered n-6 polyunsaturated fatty acid (PUFA) mol % levels, i.e., arachidonic acid (20:4n-6) in diacylphosphatidylserine (PtdSer), diacylphosphatidylinositol (PtdIns), diacylglycerophosphoethanolamine (PtdEtn), alkenylacylglycerophosphoethanolamine (PlsEtn), and diacylglycerophosphocholine (PtdCho). A notable exception was alkylacylglycerophosphocholine (PakCho), where only moderate decreases in 16:0-20:4n-6 and 18:0-20:4n-6 species were observed after fish oil supplementation. The predominant n-3 PUFA in macrophage phospholipid subclasses was docosapentaenoic acid (22:5n-3). The major n-3 species were 18:0-22:5n-3 in PtdIns, PtdSer, glycerophosphoethanolamines (EtnGpl) and 16:0-22:5n-3 in PtdCho and PlsEtn. The major n-3-containing species in PakCho were 16:0-20:5n-3 and 18:1-22:6n-3. These findings indicate that n-3 PUFA are differentially incorporated into macrophage phospholipid subclasses after dietary fish oil supplementation, and suggest that phospholipid remodeling enzymes selectively discriminate between substrates based on compatibility of sn-1 covalent linkage and the composition of the sn-1 and sn-2 aliphatic chains. Macrophage peptidoleukotriene synthesis was also strongly influenced after fish oil feeding; the LTC5/LTC4 ratio was significantly higher (P less than 0.01) in fish oil-fed animals than in corn oil-fed animals, 0.85 versus 0.01, respectively. These ratios were subsequently compared to phospholipid molecular species 20:5n-3/20:4n-6 ratios in order to determine potential sources of eicosanoid precursors.
Chapkin
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RS
Department of Animal Science, Texas A&M University, College Station 77843-2471.
Akoh
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CC
Miller
C C
CC
D000818:Animals; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D015118:Eicosapentaenoic Acid / Q000494:pharmacology*; D005260:Female; D015289:Leukotrienes / Q000096:biosynthesis*; D008264:Macrophages / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010529:Peritoneal Cavity; D010712:Phosphatidic Acids / Q000096:biosynthesis* / Q000737:chemistry; D013189:SRS-A / Q000096:biosynthesis
D004042:Dietary Fats, Unsaturated; D015289:Leukotrienes; D010712:Phosphatidic Acids; D013189:SRS-A; D015118:Eicosapentaenoic Acid