scholarly journals Evidence for a high fatty acid synthesis activity in interscapular brown adipose tissue of genetically obese Zucker rats

1982 ◽  
Vol 204 (2) ◽  
pp. 503-507 ◽  
Author(s):  
M Lavau ◽  
R Bazin ◽  
Z Karaoghlanian ◽  
C Guichard
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Synthetase ◽  
High Fatty Acid ◽  
Acid Synthesis ◽  
Zucker Rats ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose

Obese (fa/fa) rats (30 days old) exhibited a 50% increase in the weight of interscapular brown adipose tissue compared with their lean (Fa/fa) littermates. The tissue weight increase was accounted for by an increased fat content. Lipogenesis in vivo, as assessed by the incorporation of 3H from 3H2O into lipid, was increased 5-fold in brown adipose tissue of obese as compared with lean rats. Accordingly, acetyl-CoA carboxylase, fatty acid synthetase, citrate-cleavage enzyme and malic enzyme in this tissue were 4-8 times more active in obese than in lean rats.

scholarly journals Developmental changes in fatty acid synthesis in interscapular brown adipose tissue of lean and genetically obese (ob/ob) mice

1983 ◽  
Vol 212 (2) ◽  
pp. 393-398 ◽  
Author(s):  
S W Mercer ◽  
P Trayhurn
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Obese Mice ◽  
Carbohydrate Diet ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose

Fatty acid synthesis was measured in vivo with 3H2O in interscapular brown adipose tissue of lean and genetically obese (ob/ob) mice. At 26 days of age, before the development of hyperphagia, synthesis in brown adipose tissue was higher in the obese than in the lean mice; synthesis was also elevated in the liver, white adipose tissue and carcass of the obese mice. At 8 weeks of age, when hyperphagia was well established, synthesis remained elevated in all tissues of the obese mice, with the exception of brown adipose tissue. Elevated synthesis rates were not apparent in brown adipose tissue of the obese mice at 14 days of age, nor at 35 days of age. These results demonstrate that brown adipose tissue in ob/ob mice has a transitory hyperlipogenesis at, and just after, weaning on to a low-fat/high-carbohydrate diet. Once hyperphagia has developed, by week 5 of life, brown adipose tissue is the only major lipogenic tissue in the obese mice not to exhibit elevated rates of fatty acid synthesis; this suggests that insulin resistance develops much more rapidly in brown adipose tissue than in other lipogenic tissues of the ob/ob mouse.

Effect of exercise training on the rates of fatty acid synthesis in mice

1984 ◽  
Vol 62 (6) ◽  
pp. 695-699 ◽  
Author(s):  
Denis Richard ◽  
Paul Trayhurn
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
High Capacity ◽  
Acid Synthesis ◽  
Training Programme ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose

The present study has investigated the respective effects of training and exercise on the rates of fatty acid synthesis in mice. Male C57B1 10ScSn mice were trained by forced swimming in a tank at 36°C for 2 h each day for a 28-day period. Rates of fatty acid synthesis were determined in vivo by measuring the incorporation of tritium from 3H2O into tissue fatty acids. At the end of the training programme, both sedentary and trained mice were assigned to either exercising or resting groups. The results obtained show that both training and exercise affected the rates of fatty acid synthesis, regardless of whether the results are expressed per gram of tissue or per whole tissue. Training led to significant decreases in the rates of synthesis in the liver, interscapular brown adipose tissue, epididymal white adipose tissue, and the remaining carcass, particularly in resting mice. The rates of fatty acid synthesis in the major lipogenic tissues were also lower during exercise than under sedentary conditions. The reduction in synthesis in brown adipose tissue was noteworthy in view of the high capacity of this tissue for fatty acid synthesis. In conclusion, it is suggested that in exercise-trained mice carbohydrate is shunted away from the synthesis of lipid in favour of energy storage as glycogen.

scholarly journals Development of fatty acid-synthetic capacity in interscapular brown adipose tissue during suckling in genetically obese Zucker rats

1983 ◽  
Vol 216 (3) ◽  
pp. 543-549 ◽  
Author(s):  
R Bazin ◽  
M Lavau ◽  
C Guichard
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Synthetase ◽  
Fat Deposition ◽  
Synthetase Activity ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose ◽  
Fatty Acid Synthetase Activity

The development of the lipogenic capacity in brown adipose tissue was studied in suckling lean (Fa/fa) and obese (fa/fa) Zucker pups aged from 7 to 22 days. In both lean and obese pups, activities of the two key lipogenic enzymes, fatty acid synthetase and acetyl-CoA carboxylase, and of citrate cleavage enzyme rose from the early to the late suckling period. Compared with lean pups, 7-day-old fa/fa pups showed a 35% increase in fat accumulation in interscapular brown adipose tissue and a 25% increase in fatty acid synthetase activity. By 10 days of age, fat deposition, lipogenesis in vivo (assessed by the incorporation of 3H from 3H2O into fatty acids) and fatty acid synthetase activity were 1.5-2-fold higher in pre-obese than in lean pups. Compared with lean pups, the increased lipogenesis in vivo observed in brown adipose tissue of 10-day-old pre-obese pups could not entirely account for the difference in fat deposition observed in this tissue, suggesting that additional mechanisms are at play to explain the increased fat content of this tissue.

Fatty acid synthesis and generation of glycerol-3-phosphate in brown adipose tissue from rats fed a cafeteria diet

2008 ◽  
Vol 86 (7) ◽  
pp. 416-423 ◽  
Author(s):  
Valéria E. Chaves ◽  
Danúbia Frasson ◽  
Maria E.S. Martins-Santos ◽  
Luiz C.C. Navegantes ◽  
Victor D. Galban ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Glucose Uptake ◽  
Fatty Acid Synthesis ◽  
Fatty Acid Content ◽  
Acid Synthesis ◽  
Cafeteria Diet ◽  
Brown Adipose

In vivo fatty acid synthesis and the pathways of glycerol-3-phosphate (G3P) production were investigated in brown adipose tissue (BAT) from rats fed a cafeteria diet for 3 weeks. In spite of BAT activation, the diet promoted an increase in the carcass fatty acid content. Plasma insulin levels were markedly increased in cafeteria diet-fed rats. Two insulin-sensitive processes, in vivo fatty acid synthesis and in vivo glucose uptake (which was used to evaluate G3P generation via glycolysis) were increased in BAT from rats fed the cafeteria diet. Direct glycerol phosphorylation, evaluated by glycerokinase (GyK) activity and incorporation of [U-14C]glycerol into triacylglycerol (TAG)–glycerol, was also markedly increased in BAT from these rats. In contrast, the cafeteria diet induced a marked reduction of BAT glyceroneogenesis, evaluated by phosphoenolpyruvate carboxykinase-C activity and incorporation of [1-14C]pyruvate into TAG–glycerol. BAT denervation resulted in an approximately 50% reduction of GyK activity, but did not significantly affect BAT in vivo fatty acid synthesis, in vivo glucose uptake, or glyceroneogenesis. The data suggest that the supply of G3P for BAT TAG synthesis can be adjusted independently from the sympathetic nervous system and solely by reciprocal changes in the generation of G3P via glycolysis and via glyceroneogenesis, with no participation of direct phosphorylation of glycerol by GyK.

scholarly journals Physiological modulation of the uptake and fate of glucose in brown adipose tissue

1993 ◽  
Vol 295 (1) ◽  
pp. 171-176 ◽  
Author(s):  
M C Sugden ◽  
M J Holness
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
Diurnal Cycle ◽  
Acid Synthesis ◽  
Pregnant Rats ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose ◽  
Ad Libitum

Glucose utilization indices (GUI values) and rates of fatty acid synthesis in interscapular brown adipose tissue (IBAT) varied during the diurnal cycle in virgin and late-pregnant rats permitted unrestricted access to food. In virgin rats, peak GUI values and lipogenic rates were observed at the end of the dark (feeding) phase, but were not sustained during the light phase. Whereas peak GUI values were comparable with those observed during re-feeding after 24 h starvation, maximum rates of IBAT fatty acid synthesis in virgin rats during the diurnal cycle were only approx. 25% of those measured during re-feeding after 24 h starvation. Despite hyperphagia, GUI values during the diurnal cycle in late-pregnant rats fed ad libitum were generally lower than those of age-matched virgin controls. The percentage of pyruvate dehydrogenase complex present in the active form (PDHa) was also significantly decreased. Suppression of GUI and PDHa was not parallelled by suppression of fatty acid synthesis. IBAT GUI values in late-pregnant rats during chow re-feeding ad libitum after 24 h starvation were only 25% of those of corresponding virgin controls, and stimulation of fatty acid synthesis was also dramatically attenuated. The suppression of IBAT GUI values after re-feeding in pregnancy was not due to depletion of GLUT 4 protein. The results are discussed in relation to the importance of glucose as a precursor for fatty acid synthesis in IBAT.

Effect of the β-adrenoceptor agonist BRL 26830 on fatty acid synthesis and on the activities of pyruvate dehydrogenase and acetyl-CoA carboxylase in adipose tissues of the rat

1989 ◽  
Vol 9 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Shelagh Wilson
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Diabetic Rats ◽  
Adipose Tissues ◽  
Adrenoceptor Agonist ◽  
Brown Adipose

BRL 26830 is a thermogenic β-adrenoceptor agonist which stimulates lipolysis and fatty acid oxidation in vivo. It also stimulates insulin secretion, and hence promotes glucose utilisation in vivo. The effect of this agent on white and brown adipose tissue of the rat was investigated. BRL 26830 increased the rate of fatty acid synthesis in vivo in white adipose tissue by 135% but reduced the rate of fatty acid synthesis in vivo in brown adipose tissue by 78%. The increase was abolished in white adipose tissue of streptozotocin-diabetic rats, indicating that the effect involved a rise in circulating insulin levels. The reduction in fatty acid synthesis in brown adipose tissues was associated with a reduction in the activity of acetyl-CoA carboxylase in the tissue consistent with a direct β-adrenoceptor-mediated effect. BRL 26830 also increased the proportion of pyruvate dehydrogenase in its active form in vivo in brown adipose tissue and this increase was abolished in streptozotocin-diabetic rats. These findings illustrate different sensitivities of white and brown adipose tissues to combined β-adrenergic and insulin stimulation.

scholarly journals Modulation in vivo of β-adrenergic-receptor subtypes in rat brown adipose tissue by the thermogenic agonist Ro 16–8714

1992 ◽  
Vol 286 (3) ◽  
pp. 743-746 ◽  
Author(s):  
J P Revelli ◽  
P Muzzin ◽  
J P Giacobino
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Plasma Membranes ◽  
State Level ◽  
Zucker Rats ◽  
Receptor Subtypes ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose ◽  
Beta Adrenergic Agonist

The number of beta 3-adrenergic receptors (AR) in plasma membranes from interscapular brown adipose tissue (IBAT) was decreased by 62% in lean Zucker rats treated with the thermogenic beta-adrenergic agonist Ro 16-8714 as compared with controls after 72 h of treatment. The loss of beta 3-AR number was preceded by a 93% decrease in the steady-state level of beta 3-AR mRNA at 30 h. Similar results were obtained in obese (fa/fa) Zucker rats. Ro 16-8714 had no effect on the number of beta 1- and beta 2-ARs in IBAT. This is the first report to demonstrate that the beta 3-AR in IBAT can be specifically down-regulated in vivo by exposure to a thermogenic agonist.

scholarly journals Evidence that fatty acid synthesis in the interscapular brown adipose tissue of cold-adapted rats is increased in vivo by insulin by mechanisms involving parallel activation of pyruvate dehydrogenase and acetyl-coenzyme A carboxylase

1977 ◽  
Vol 166 (3) ◽  
pp. 627-630 ◽  
Author(s):  
J G McCormack ◽  
R M Denton
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fatty Acid Synthesis ◽  
Pyruvate Dehydrogenase ◽  
Plasma Insulin ◽  
Acid Synthesis ◽  
Interscapular Brown Adipose Tissue ◽  
Cold Adapted ◽  
Brown Adipose

Plasma insulin concentrations in cold-adapted rats were altered acutely by administration of glucose or anti-insulin serum. Rates of fatty acid synthesis in interscapular brown adipose tissue were determined from the incorporation of 3H from 3H2O into tissue lipid. Rates of synthesis were greatly elevated after glucose administration and markedly decreased after injection with anti-insulin serum. Parallel changes in the initial activities of both acetyl-CoA carboxylase and pyruvate dehydrogenase were observed under these conditions, but no changes in total activities were evident. The results suggest that this tissue is an important site of fatty acid synthesis in the cold-adapted rat and that this feature of the tissue is sensitive to changes in plasma insulin concentrations.

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