Effect of various n-3/n-6 fatty acid ratio contents of high fat diets on rat liver and heart peroxisomal and mitochondrial beta-oxidation
1993
Vamecq, J. | Vallee, L. | Porte, P.L. de la | Fontaine, M. | Craemer, D. de | Branden, C. van den | Lafont, H. | Grataroli, R. | Nalbone, G.
The present work extends tissue investigations previously performed in rat gastric mucosa on lipid metabolism alterations caused by n - 3 and n - 6 fatty acid-enriched diets. Liver and heart tissues are here studied and demonstrated to undergo, upon exposure to high fat diets with various n - 3/n - 6 fatty acid ratio contents, biochemical and morphological changes which may be enumerated as follows: (1) Rat liver peroxisomal prostaglandin E(2), fatty acid but not bile acid beta-oxidation rates are enhanced, especially upon the diet with the higher n - 3/n - 6 fatty acid ratio. Mitochondrial beta-oxidation rates are little or not affected by the high fat diets. (2) Rat liver carnitine acyltransferases are stimulated by the high fat diets, the more rich the n - 3 fatty acid content, the more pronounced the stimulatory effect. (3) Rat heart peroxisomal and mitochondrial beta-oxidation rates were increased in animals receiving the n - 3 fatty acid-enriched diet. At a low n - 3/n - 6 fatty acid ratio content of the diet, these oxidizing rate values were in control range. The carnitine acyltransferase activities were increased in rat heart to different extents, depending on the n - 3/n - 6 fatty acid ratio content of the diet. (4) Ultrastructural examination and morphometric determinations on hepatocytes from rats receiving the diets with the lowest and the highest n - 3/n - 6 fatty acid ratio contents disclose that in the latter case the numbers and fractional volumes of peroxisomes and mitochondria are significantly higher than in the former case.
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