The effect of dietary n−6 and n−3 polyunsaturated fatty acids on blood pressure and tissue fatty acid composition in spontaneously hypertensive rats

Effects of dietary n-6 and n-3 fatty acids (FAs) on blood pressure (BP) and tissue phospholipid (PL) FA composition in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats were compared. Male weanling SHR and WKY were fed a fat-free semisynthetic diet supplemented with 10% (w/w) fats containing (a) 78% 18:2n-6 (LA-rich), (b) 20% LA and 55% 18:3n-3 (LN-rich), or (c) 11% LA and 3% LN (CON) for seven weeks. Dietary fats did not affect the BP elevation, but significantly altered the FA composition of brain, adrenal gland, renal medulla and cortex PL in SHR. The LA-rich diet increased n-6 FA while it reduced n-3 FA levels. The levels of 20:4n-6 were not significantly different between animals fed the LA-rich and the CON diets. LN-rich diet increased the levels of n-3 FAs, while it reduced those of n-6 FAs. However, the extent of change was significantly less in SHR than in WKY. In all dietary groups, SHR, as compared to WKY, had a relatively higher level of the 2 series prostaglandin (PG) precursor, 20:4n-6, and a relatively lower level of the 1 and 3 series PG precursors, 20:3n-6 and 20:5n-3. The possibility that the unbalanced eicosanoid FA precursor levels might contribute to the development of hypertension in this animal model is discussed.