Characterization of the stimulatory effect of high-fat diets on peroxisomal beta-oxidation in rat liver.
1. The effect on rat liver peroxisomal beta-oxidation of feeding diets containing various amounts of dietary oils was investigated. With increasing amounts (5-25%, w/w) of soya-bean oil an apparent, but not statistically significant, increase of 1.5-fold was found both in specific activity, and in total liver activity. Increasing amounts of partially hydrogenated marine oil revealed a sigmoidal dose-response-curve, giving a 4-6-fold increase in the peroxisomal beta-oxidation activity at 20% or more of this oil in the diet. 2. Addition of small amounts of soya-bean oil to the marine-oil diet had no effect on the peroxisomal beta-oxidation activity, but decreased the C20:3(5,8,11) fatty acid/C20:4(5,8,11,14) fatty acid ratio in liver phospholipids from 0.74 to 0.01. 3. Starvation for 2 days led to a 1.5-1.8-fold increase in the peroxisomal beta-oxidation activity in rats previously fed on a standard pelleted diet, but had no effect in rats given high-fat diets. 4. Feeding partially hydrogenated marine oil or partially hydrogenated rape-seed oil resulted in higher activities than the corresponding unhydrogenated oils. 5. No significant differences in the effect on peroxisomal beta-oxidation could be detected between diets containing rape-seed oils with 15 or 45% erucic acid respectively. 6. These findings are discussed in relation to the possible effects of C22:1 and trans fatty acids in the process leading to increased peroxisomal beta-oxidation activity in the liver.
D000818:Animals; D002994:Clofibrate / Q000494:pharmacology; D004041:Dietary Fats / Q000494:pharmacology*; D005228:Fatty Acids, Essential / Q000494:pharmacology; D006865:Hydrogenation; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008830:Microbodies / Q000187:drug effects / Q000378:metabolism*; D009821:Oils / Q000494:pharmacology; D009940:Organoids / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains; D013217:Starvation; D013268:Stimulation, Chemical
D004041:Dietary Fats; D005228:Fatty Acids, Essential; D009821:Oils; D002994:Clofibrate