title: Suppression of fatty acid synthase by dietary polyunsaturated fatty acids is mediated by fat itself, not by peroxidative mechanism.
abstract: This study examined the effect of dietary polyunsaturated fatty acids (PUFA) that were supplemented with vitamin E on lipid peroxidation, glutathione-dependent detoxifying enzyme system activity, and lipogenic fatty acid synthase (FAS) expression in rat liver. Male Sprague-Dawley rats were fed semipurified diets containing either 1% (w/w) corn oil or 10% each of beef tallow, corn oil, perilla oil, and fish oil for 4 wk. Alpha-tocopherol was supplemented in perilla oil (0.015%) and fish oil (0.019%). Hepatic thiobarbituric acid reactive substances, an estimate of lipid peroxidation, were not significantly different among the dietary groups. The glutathione peroxidase, glutathione reductase, and glutathione S-transferase activities were all elevated by the polyunsaturated fats, especially fish oil. The activity of FAS was reduced in the polyunsaturated fat-fed groups in the order of fish oil, perilla oil, and corn oil. The mRNA contents decreased in rats that were fed the 10% fat diets, particularly polyunsaturated fats, compared with the rats that were fed the 1% corn oil diet. Similarly, the inhibitory effect was the greatest in fish oil. These results suggest that lipid peroxidation can be minimized by vitamin E; PUFA in itself has a suppressive effect on lipogenic enzyme.
authors.affiliation: Department of Food and Nutrition, Seoul National University, Seoul 151-742, Korea.
authors.forename: Hyekyeong
authors.initials: H
authors.lastname: Kim
authors.forename: Sungwon
authors.initials: S
authors.lastname: Choi
authors.forename: Hae-Jeung
authors.initials: HJ
authors.lastname: Lee
authors.forename: Joo-Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Haymie
authors.initials: H
authors.lastname: Choi
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D003314:Corn Oil / Q000008:administration & dosage; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D004789:Enzyme Activation / Q000187:drug effects; D005223:Fats / Q000008:administration & dosage; D064429:Fatty Acid Synthases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis; D005395:Fish Oils / Q000008:administration & dosage; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D050356:Lipid Metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008054:Lipid Peroxides / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008297:Male; D010938:Plant Oils / Q000008:administration & dosage; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017962:alpha-Linolenic Acid / Q000008:administration & dosage
chemical_list: D004042:Dietary Fats, Unsaturated; D005223:Fats; D005227:Fatty Acids; D005395:Fish Oils; D008054:Lipid Peroxides; D010938:Plant Oils; D012333:RNA, Messenger; D017962:alpha-Linolenic Acid; C058216:perilla seed oil; D003314:Corn Oil; C013698:tallow; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D064429:Fatty Acid Synthases; D005982:Glutathione Transferase