Diet fat alters expression of genes for enzymes of lipogenesis in lean and obese mice.
The objective of this experiment was to determine the effect of polyunsaturated fatty acids on gene expression for fatty acid synthase, acetyl CoA-carboxylase, malic enzyme, pyruvate kinase, and phosphoenolpyruvate carboxykinase in obese mice. Eight-week-old female lean and obese mice were fed semi-purified diets containing 20% (w/w) fat of either high or low polyunsaturated to saturated (P/S) fatty acid ratio for four weeks. Total RNA was isolated from liver and was hybridized to cDNA probes for the above enzymes. Consumption of a high P/S diet decreased mRNA levels for all the lipogenic enzymes studied in both lean and obese mice. Compared to lean mice, obese mice exhibited a higher mRNA level for fatty acid synthase, acetyl CoA-carboxylase, malic enzyme, and pyruvate kinase in animals fed either a high or low P/S diet. Enzyme-specific activities followed the same profile as the mRNA levels in both lean and obese mice fed a high or low P/S diet. The decrease in liver fatty acid synthase mRNA level was more pronounced in lean mice compared to obese mice, suggesting that the obese mice may be more resistant to polyunsaturated fatty acid feedback control of gene expression.
Cheema
S K
SK
Department of Agricultural, Food and Nutritional Science and Metabolism Research Group, University of Alberta, Edmonton, Canada.
Clandinin
M T
MT
D000103:Acetyl-CoA Carboxylase / Q000235:genetics; D000818:Animals; D001835:Body Weight; D050260:Carbohydrate Metabolism; D004032:Diet; D004041:Dietary Fats / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D008055:Lipids / Q000096:biosynthesis*; D008099:Liver / Q000201:enzymology; D008291:Malate Dehydrogenase / Q000235:genetics; D051379:Mice; D008820:Mice, Obese; D009765:Obesity / Q000235:genetics / Q000378:metabolism*; D009929:Organ Size; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000235:genetics; D011770:Pyruvate Kinase / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis
D004041:Dietary Fats; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D012333:RNA, Messenger; D008291:Malate Dehydrogenase; C030574:malate dehydrogenase (decarboxylating); D011770:Pyruvate Kinase; D010729:Phosphoenolpyruvate Carboxykinase (GTP); D000103:Acetyl-CoA Carboxylase