Effect of fish oil on the unsaturated fatty acid metabolism in dyslipidemic sucrose fed rats.

BRENNER, R. R.; BERNASCONI A.M.; MONTANARO M.A.; PELLON MAISON, M.; FINARELLI, G.; HEIN, G.; CHICCO A; LOMBARDO Y.B.

Maastricht, Holanda.

Congreso; 49 International Conference on the Bioscience of Lipids.; 2008

ICBL

A sucrose-rich diet (SRD) compared to a starch diet  induces in the rat time-dependent metabolic disorders and insulin resistance similar to the metabolic syndrome and like those found in diabetes type 2 with hypertriglyceridemia, evolving after 8 months to a normoinsulinemia. In this study we examined how dietary n-3 FA modify hepatic nuclear receptors LXR, PPAR-á, transcription factor SREBP-1c, desaturases ∆9, ∆6 and ∆5 mRNA and activity and the composition of FA and phospholipids molecular species in rats feeding the SRD for a long term. SRD, in animals feeding 8% corn oil, enhanced the ∆6 desaturase and less significantly the ∆5. The replacement of 8% corn oil by 1% corn oil plus 7% cod oil for two months decreased the SCD-1 parameters, but did not modify the ∆6 and ∆5 desaturases in control animals. It did not modify these parameters and the insulinemia in rats feeding the SRD. In total liver and microsomal lipids the SRD evoked no significant variation of monoenoic acid percentage, but increased  20:4n-6 and  decreased  22:6n-3. The incorporation of fish oil in both diets evoked similarly no variation of monoenoic acids, a decrease of 20:4n-6 and increases of all the n-3 acids. These results suggest that the changes evoked by the fish oil are mainly produced by competition between dietary n-6 and n-3 acids and not through desaturases activity modification. The function of LXR, PPAR-á and SREBP-1c is discussed.