title: Specific inhibition of hepatic fatty acid synthesis exerted by dietary linoleate and linolenate in essential fatty acid adequate rats.
abstract: Dietary linoleate and linolenate were investigated for their ability to specifically inhibit liver and adipose tissue lipogenesis in meal-fed (access to food 900-1,200 hr), essential fatty acid (EFA) adequate rats. Supplementing a high carbohydrate diet containing 2.5% safflower oil with 3% palmitate 16:0, oleate 18:1, or linoleate 18:2 did not affect in vivo liver or adipose tissue fatty acid synthesis. However, 18:2 addition to the basal diet did result in a significant (P less than 0.05) decline of liver fatty acid synthetase (FAS) and glucose-6-phosphate dehydrogenase (G6PD) activities. When the safflower oil content of the basal diet was reduced to 1%, the addition of 3% 18:2 or linolenate 18:3 significantly (P less than 0.05) depressed hepatic FAS, G6PD, and in vivo fatty acid synthesis by 50%. Addition of 18:1 caused no depression in hepatic FAS activity but did result in a significant (P less than 0.05) decline in liver G6PD activity and fatty acid synthesis which was intermediate between basal and basal +18:2- or +18:3-fed animals. Adipose tissue rates of lipogenesis were completely unaffected by dietary fatty acid supplementation. Similarly, the addition of 3 or 5% 18:3 to a basal diet for only one meal resulted in no change in lipogenesis relative to that in animals fed the basal diet. The data indicate that, like rats fed EFA-deficient diets, dietary 18:2 and 18:3 exert a specific capacity to depress rat liver FAS and G6PD activities and rate of fatty acid synthesis.
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D004041:Dietary Fats; D064429:Fatty Acid Synthases / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D008041:Linoleic Acids / Q000494:pharmacology*; D008042:Linolenic Acids / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism*; D008291:Malate Dehydrogenase / Q000378:metabolism; D008297:Male; D051381:Rats
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D008041:Linoleic Acids; D008042:Linolenic Acids; D008291:Malate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D064429:Fatty Acid Synthases