Eicosappentaenoic Docosahexaenoic Acids Reduce Arachidonic Acid Release by Rat Kidney Microsomes

• Published in: BMB reports Vol. 32; no. 1; pp. 33 - 38
• Main Authors: Young Keun Yeo, Ah Young Lim, Ji Yoon Lee, Hyo Jung Kim, Tibor Farkas, Dae Gon Kim
• Format: Journal Article
• Language: Korean
• Published: 생화학분자생물학회 30.01.1999
• ISSN: 1976-6696

The effects of eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acids (DHA, 22:6n-3) on the phospho-lipase A₂ (PLA₂)-mediated release of arachidonic acid (AA, 20:4n-6) were studied in kidney microsomes from rats fed diets containing sunflower oil (SO) or fish oil (FO) concentrate for 11 months. The amounts of AA released by the endogenous PLA₂ enzyme were significantly lower by 38% in the FO, compared to the SO-fed rats (23.2 n㏖ versus 60.7 n㏖ AA released/ ㎎ protein/h in the FO- and SO-treated groups, respectively). The FO-derived microsomes released less linoleic acid (LA, 18:2n-6) and adrenic acid (22:4n-6), but larger amounts of the n-3 fatty acids, including EPA, DHA, docosapentaenoic acid (DPA, 22:5n-3), and 20:4n-3 than the SO-derived microsomes. A similar replacement of the AA and adrenic acid with the n-3 fatty acids including EPA and DHA was also observed in the microsomal phospholipid fraction from the FO-fed rats relative to the SO-treated group. The results suggest that the PLA₂-mediated release of AA is reduced and that of EPA is increased in compensation for AA decline in kidney microsomes from FO-fed rats (0.7 n㏖ EPA/㎎ protein/h versus 22.7 n㏖ EPA/㎎ protein/h for the SO and FO-treated groups). Replacement of the n-6 with n-3 fatty acids may explain the reduced synthesis of the AA-derived prostaglandins and the concomitant rise in the EPA-derived prostaglandins observed in kidneys of FO-treated rats.