Influence of dietary lipid on lipogenesis and on the activity of malic enzyme and citrate cleavage enzyme in liver of the growing chick.
About: This article is published in Journal of Nutrition.The article was published on 1970-08-01. It has received 83 citations till now. The article focuses on the topics: Malic enzyme & Dietary lipid.
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TL;DR: The available evidence suggests that in the chicken, and presumably other avian species, fatty acids are synthesized in liver and are transported as triglycerides in the plasma low-density lipoproteins to the adipose tissue for storage.
291 citations
TL;DR: In this paper, the effect of diet on the activity of enzymes involved in fatty acid and cholesterol synthesis is discussed. But, the authors do not consider the effects of dietary manipulations on liver and adipose tissue.
Abstract: Publisher Summary This chapter discusses the effect of diet on activity of enzymes involved in fatty acid and cholesterol synthesis. Adipose tissue is the major organ contributing to de novo fatty acid synthesis in the nonlactating pig and ruminant, while the liver is more important in birds and man. In rats and mice, both organs contribute significantly to de novo fatty acid synthesis. In species such as the rat, where both liver and adipose tissue contribute to de novo fatty acid synthesis, dietary manipulations generally affect both tissues in a similar fashion; however, there are exceptions. The quantity of hepatic fatty acid synthetase can regulate the rate of fatty acid synthesis in rats fed high-carbohydrate diets. Unlike enzymes involved in fatty acid synthesis, a change in β -Hydroxy- β -methylglutaryl-CoA reductase activity precedes changes in hepatic acetate conversion to cholesterol. Allosteric control of enzyme activity plays a major role in the rapid regulation of metabolic flux. Adaptive changes in enzyme content reflect sustained changes in metabolic flux and such adaptations are involved in the longer term regulation of metabolism.
109 citations
TL;DR: It is shown that Ci8:2 and Ci8-3 specifically inhibit rat liver fatty acid synthesis, independent of carbohydrate intake, and under these conditions adipose tissue lipogenesis was unaffected by low levels of dietary fat regardless of the degree of unsaturation.
Abstract: Four experiments were conducted to investigate what influence methyl esters of Ci«:o,Ci8:o, Ci8:i, C18:2, and Cis-.a fatty acids exert on rat liver and adipose tissue fatty acid synthesis and related enzymes when supplemented to a fat-free diet (FF). A randomized complete block design, in which rats were matched for body weight and food intake, was utilized. Rats previously adapted to a meal-eating regimen (access to food from 0900 to 1200 hours ) were fed a FF-diet for 7 days prior to the addition of the respective dietary fatty acids. In experiments 1 to 3, all esters were supplemented at a level of 3% of the daily FF-diet allotment. The apparent absorbabilities of C18:0 and Ci8:u were determined to be 40% and 35%, while values for Ci8:i, GI«^,and Ci8:3 were 88%, 87%, and 89%, respec tively. In comparison to the FF dietary treatment, polyunsaturated fatty acids (Ci8:2 and C^s) were able in three of four experiments to reduce the rate of hepatic fatty acid synthesis and the activities of hepatic fatty acid synthetase (FAS) and malic enzyme (ME). In all four experiments, glucose-6-phosphate dehydrogenase (G6PD) activity was significantly de pressed by Ci8:2 and CiR:3. Ci8:i produced an intermediate rate of in vitro liver fatty acid synthesis, but exerted no significant effect on hepatic lipo- genic enzyme activities. Adding Ci6:0 or Ci8:0 to the FF-diet had no de pressive effect on hepatic fatty acid synthesis, but Ci8;0 supplementation was associated with a significant increase in hepatic FAS, G6PD and ME activities. Neither unsaturated nor saturated fatty acids affected adipose tissue FAS, G6PD or ME activities or rates of fatty acid synthesis. The lack of influence of Ci6:u and Ci8:0 may have been partially due to their poor absorbability. Therefore, in experiment 4 a level of 7% Cieio supple mentation was compared to 3% C\g-.2or Ci8:3. This resulted in comparable amounts of fatty acid absorbed. Both Ci8:a and Cis-.a addition to the FF- diet were equally effective in significantly depressing in vivo hepatic fatty acid synthesis, and FAS, G6PD and ME activities by more than 50%. Cie:o had no suppressive action on liver fatty acid synthesis or related enzyme activities. Again adipose tissue lipogenesis remained unchanged by dietary fat treatment. These data clearly demonstrate that Ci8:2 and Ci8:3 specifically inhibit rat liver fatty acid synthesis, independent of carbohydrate intake. Under these conditions adipose tissue lipogenesis was unaffected by low levels of dietary fat regardless of the degree of unsaturation. J. Nutr. 107: 1170-1181,1977.
105 citations
TL;DR: The results of this study indicate that dietary lipid depresses hepatic lipogenic enzyme activities and that the liver may be a more important site for fatty acid synthesis than is adipose tissue in coho salmon.
Abstract: HUANGSHENG LIN, DALE R. ROMSOS,PETER I. TACK ANDGILBERT A. LE VEILLEDepartments of Fisheries and Wildlife and Food Scienceand Human Nutrition, Michigan State University,East Lansing, Michigan 48824ABSTRACT Coho salmon (Oncorhynchus kisutch), 8 to 18 months ofage, were maintained in culture tanks and were fed three semipurifieddiets. The diets contained 40% of energy from protein and 11.5%, 23%, or46% of energy from lipid. The body weight gain and food conversionfactors were similar among groups of fish fed the diets in each of thethree experiments. Wet weight of mesenteric adipose tissue increased withincreased amount of lipid in the diet; however, epaxial muscle lipid content was not influenced by the lipid content of the diet. Several hepaticand adipose tissue lipogenic enzymes (fatty acid synthetase, citrate cleavageenzyme, malic enzyme, glucose-6-phosphate dehydrogenase, 6-phospho-gluconate dehydrogenase, and NADP-isocitrate dehydrogenase) were assayed. These lipogenic enzymes exhibited high activities in liver and relatively low concentration in adipose tissue of the fish. The activities of allthe hepatic lipogenic enzymes assayed, except for NADP-isocitrate dehydrogenase, were depressed as the level of lipid in the diet was increased;however, the activities of these enzymes in mesenteric adipose tissue werenot influenced by the diets fed. The results of this study indicate thatdietary lipid depresses hepatic lipogenic enzyme activities and that theliver may be a more important site for fatty acid synthesis than is adiposetissue in coho salmon. J. Nutr. 107: 846-854, 1977.INDEXING KEY WORDS lipogenic enzymes •dietary fat •liver•adipose tissue •coho salmonFish diets are generally high in fat and process. To this end, the activities of se-low in carbohydrate (1). There is a paucity lected lipogenic enzymes were measured irof data on the ability of fish to metabolize liver and mesenteric adipose tissue of cohcreadily digestible sources of carbohydrate, salmon fed high-carbohydrate and high-For example, while the sites of conver- fat diets for several weeks.sion of dietary carbohydrate to fatty acidshave been investigated in numerous other MATERIALSAND METHODSspecies (2-11), the relative importance ofliver and adipose tissue as sites for con- Fish culture system and diets. Fresiversion of carbohydrate to fatty acids in water coho salmon (Oncorhynchus kisutcifish has not been elucidated. (Walbaum)) eggs were obtained from aiThe purpose of this report was to obtaininformation on the site of fatty acid syn- Jf! l h Em AM«MTDRR
103 citations
TL;DR: The data indicate that dietary n-3 lipid sources influence the fatty acid composition of tissues and can be effectively used to enrich chicken meat with n- 3 polyunsaturated fatty acids.
82 citations
References
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Journal Article•
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
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TL;DR: In this paper, the authors described a simplified version of the method and reported the results of a study of its application to different tissues, including the efficiency of the washing procedure in terms of the removal from tissue lipides of some non-lipide substances of special biochemical interest.
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