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Decreasing the dietary n‐6/n‐3 fatty acid ratio uniquely increases eicosapentaenic acid in heart membrane phospholipids with no effect on GLUT 4 expression in piglets
Author(s) -
Novak Elizabeth Marie,
Innis Sheila Margaret
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1028
Subject(s) - arachidonic acid , docosahexaenoic acid , eicosapentaenoic acid , phospholipid , chemistry , metabolism , linoleic acid , fatty acid , endocrinology , medicine , western blot , biochemistry , polyunsaturated fatty acid , biology , membrane , enzyme , gene
The omega 3 fatty acids (FA), alpha linolenic acid (ALA, 18:3n‐3), eicosapentaenoic acid (EPA, 20:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3) are associated with decreased cardiovascular (CVD) and inflammatory disease. The omega 6 linoleic acid (LA, 18:2n‐6) has favorable effects on CVD through effects on plasma lipids. However, high intakes of LA may inhibit ALA metabolism to EPA and DHA, resulting in decreased tissue n‐3 FA and increased arachidonic acid (ARA, 20:4n‐6) to EPA ratios. N‐6 and n‐3 FA also regulate expression of genes for proteins of FA and glucose metabolism, and in skeletal muscle n‐3 FA increase GLUT 4 expression, thus favoring glucose oxidation. The effect of dietary LA/ALA ratio on heart phospholipid (PL) FA and GLUT 4 expression is not known. We determined the effect of dietary n‐6 and n‐3 FA on heart membrane phospholipid FA and GLUT 4 expression. Piglets were fed (%energy) 1.5% LA+0.06% ALA, 1.5% LA+1.2% ALA, 9% LA+1.2% ALA, or 9% LA+1.2% ALA with 0.6% ARA+0.8% DHA for 30 days. Membrane PL and FA were determined by HPLC and GLC. GLUT 4 membrane and cytosol expression and distribution was determined by Western blot. Piglets fed 1.5%LA+1.2%ALA had higher EPA and lower ARA and ARA/EPA in all heart PL compared to the other diets, demonstrating the LA/ALA ratio, not ALA intake determines EPA incorporation. Regardless of the difference in membrane FA, we found no difference in GLUT 4 expression.