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.

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.

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.

The influence of starvation and natural refeeding on the rate of triacylglycerol/fatty acid substrate cycling in brown adipose tissue and different white adipose sites of the rat in vivo. The role of insulin and the sympathetic nervous system

1988 ◽  
Vol 8 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Stewart W. Mercer ◽  
Dermot H. Williamson
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Fold Increase ◽  
Chow Diet ◽  
Fatty Acid Substrate ◽  
Brown Adipose ◽  
Acute Increase ◽  
Acid Substrate

Triacylglycerol/fatty acid substrate cycling was measured in vivo in brown adipose tissue (BAT) and white adipose tissue (WAT) of fed, starved and refed rats. Starvation (24 h) significantly decreased the rate of cycling in BAT, and refeeding chow diet led to a rapid, 6-fold increase in cycling. Cycling rate in WAT was much lower than in BAT, and was not influenced by fasting or refeeding. Similar rates of cycling were found in epididymal, mesenteric, subcutaneous, and scapular WAT depots. Sympathetic denervation of interscapular BAT abolished the response of the tissue to refeeding, as did acute suppression of insulin secretion. Similarly, rats fasted for 3 days showed no acute increase in the activity of the cycle following refeeding.

Uptake of glucose and release of fatty acids and glycerol by rat brown adipose tissue in vivo

1986 ◽  
Vol 64 (5) ◽  
pp. 609-614 ◽  
Author(s):  
Stephanie W. Y. Ma ◽  
David O. Foster
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Tissue Blood Flow ◽  
Glycerol Release ◽  
Maximal Stimulation ◽  
Brown Adipose ◽  
Lactate And Pyruvate

The net in vivo uptake or release of free fatty acids glycerol, glucose, lactate, and pyruvate by the interscapular brown adipose tissue (IBAT) of barbital-anesthetized, cold-acclimated rats was determined from measurements of plasma arteriovenous concentration differences across IBAT and tissue blood flow. Measurements were made without stimulation of the tissue and also during submaximal and maximal stimulation by infused noradrenaline (NA), the physiological activator of BAT thermogenesis. There was no appreciable uptake of glucose or release of fatty acids and glycerol by the nonstimulated tissue. At both levels of stimulation there was significant uptake of glucose (1.7 and 2.0 μmol/min) and release of glycerol (0.9 and 1.2 μmol/min), but only at maximal stimulation was there significant release of fatty acids (1.9 μmol/min). Release of lactate and pyruvate accounted for 33% of the glucose taken up at submaximal stimulation and 88% at maximal stimulation. By calculation, the remainder of the glucose taken up was sufficient to have fueled about 12% of the thermogenesis at submaximal stimulation, but only about 2% at maximal stimulation. As estimated from the rate of glycerol release, the rate of triglyceride hydrolysis was sufficient at submaximal stimulation to fuel IBAT thermogenesis entirely with the resulting fatty acids, but it was not sufficient to do so at maximal stimulation when some of the fatty acid was exported. It is suggested that at maximal NA-induced thermogenesis a portion of lipolysis proceeded only to the level of mono- and di-glycerides with the result that glycerol release did not fully reflect the rate of fatty acid formation. Both in absolute terms and in relation to the export of glycerol the in vivo export of fatty acids from the adipocytes of IBAT was much less than is observed with brown adipocytes in vitro.

Transient upregulation of IGF-I gene expression in brown adipose tissue of cold-exposed rats

1997 ◽  
Vol 272 (3) ◽  
pp. E453-E460 ◽  
Author(s):  
C. Duchamp ◽  
K. A. Burton ◽  
A. Geloen ◽  
M. J. Dauncey
Keyword(s):  
Adipose Tissue ◽  
Food Intake ◽  
Brown Adipose Tissue ◽  
Unit Weight ◽  
Mrna Levels ◽  
Interscapular Brown Adipose Tissue ◽  
Total Rna ◽  
Brown Adipose ◽  
Igf I

The possible involvement of locally produced insulin-like growth factor I (IGF-I) in the cold-induced hyperplasia of interscapular brown adipose tissue (BAT) was investigated in 2-, 4-, and 7-day cold-exposed (CE, 4 degrees C) rats by measuring BAT IGF-I expression at a time when extensive BAT cell proliferation occurs. By comparison with thermoneutral (25 degrees C) controls, plasma IGF-I decreased in CE rats despite an increased food intake, whereas BAT IGF-I peptide increased markedly to peak after 4 days at 4 degrees C. The ratio of class 1 to class 2 IGF-I mRNA was much higher in BAT than in liver. BAT IGF-I mRNA levels per unit weight total RNA doubled after 2 days at 4 degrees C but decreased thereafter to the level in controls. Upregulation of BAT IGF-I mRNA also occurred in CE rats with a food intake restricted to the level of controls. The transient cold-induced upregulation of BAT IGF-I (per unit weight total RNA) suggests that IGF-I plays a role in the early cold-induced BAT hyperplasia that occurs in vivo.

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