Effect of Dietary Linoleic, Alpha-Linolenic and Arachidonic Acids on Lipid Metabolism, Tissue Fatty Acid Composition and Eicosanoid Production in Rats.
Effect of Dietary Linoleic, Alpha-Linolenic and Arachidonic Acids on Lipid Metabolism, Tissue Fatty Acid Composition and Eicosanoid Production in Rats.
Year: 1996
Authors: I Ikeda, K Mitsui, K Imaizumi.
Publication Name: J. Nutr. Sci. Vitaminol.
Publication Details: Volume 42; Number 6; Page 541.
Abstract:
In this study, the effect of dietary AA on the lipid content of serum and liver, the FA composition of tissue PLs and on eicosanoid production were compared to LA and ALA in diets with a constant PUFA/MUFA/SFA ratio. Rats were fed semi-purified diets containing 10% fat from vegetable oils and with a PUFA/MUFA/SFA ratio of 1:1:1. LA was the sole PUFA in the LA dietary group. ALA and AA represented 1% of the diet (10% of dietary FAs) and were fed at the expense of LA in both the ALA and AA groups, respectively. The diets were fed for 3 weeks. The concentration of serum TG, PLs and liver TG were significantly lower in the ALA and AA groups than in the LA group. Lower TG synthesis in the liver could result in decreased synthesis and secretion of TG and VLDL. Hepatic PLs were significantly higher in the ALA and AA groups than in the LA group. Compared to the LA group, the percentages of AA in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in the liver and heart were significantly lower in the ALA group and significantly higher in the AA groups. Dietary AA, but not ALA, resulted in a marked reduction of LA and increased AA and n-6 docosapentaenoic acids in heart cardiolipin. Platelet TXA2 production was significantly lower in the ALA group as compared to the LA and AA groups. There was no difference in TXA2 production between the LA and AA groups suggesting that the synthesis of these eicosanoids reaches a maximum when the level of AA in tissue PLs is equal to that of LA. The aortic production of PGI2 was the same among the three groups. The ratios of TXA2 and PGI2 in the LA and AA groups were comparable, and were significantly higher than that of the ALA group. The results demonstrate that dietary AA enriches the AA content in tissue PLs more effectively than LA. The effects of AA and LA on the production of TXA2 and PGI2 were comparable. In contrast, ALA consistently lowered the production of TXB2 and the ratio of TXB2:PGI2. The authors suggested that their findings regarding the metabolic effects of AA feeding may be of benefit in infants who require AA and in patients with abnormal AA metabolism.
