Endogenous Fatty Acid Synthesis Drives Brown Adipose Tissue Involution

1. The effect of nutritional status on fatty acid synthesis in brown adipose tissue was compared with the effect of cold-exposure. Fatty acid synthesis was measured in vivo by 3H2O incorporation into tissue lipids. The activities of acetyl-CoA carboxylase and fatty acid synthetase and the tissue concentrations of malonyl-CoA and citrate were assayed. 2. In brown adipose tissue of control mice, the tissue content of malonyl-CoA was 13 nmol/g wet wt., higher than values reported in other tissues. From the total tissue water content, the minimum possible concentration was estimated to be 30 microM 3. There were parallel changes in fatty acid synthesis, malonyl-CoA content and acetyl-CoA carboxylase activity in response to starvation and re-feeding. 4. There was no correlation between measured rates of fatty acid synthesis and malonyl-CoA content and acetyl-CoA carboxylase activity in acute cold-exposure. The results suggest there is simultaneous fatty acid synthesis and oxidation in brown adipose tissue of cold-exposed mice. This is probably effected not by decreases in the malonyl-CoA content, but by increases in the concentration of free long-chain fatty acyl-CoA or enhanced peroxisomal oxidation, allowing shorter-chain fatty acids to enter the mitochondria independent of carnitine acyltransferase (overt form) activity.

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

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y08-052 ◽

2008 ◽

Vol 86 (7) ◽

pp. 416-423 ◽

Cited By ~ 12

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.

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

Biochemical Journal ◽

10.1042/bj2950171 ◽

1993 ◽

Vol 295 (1) ◽

pp. 171-176 ◽

Cited By ~ 6

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.

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High-energy diets produce different effects on fatty acid synthesis in brown adipose tissue, white adipose tissue and liver in the rat

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism ◽

10.1016/0005-2760(83)90043-7 ◽

1983 ◽

Vol 750 (2) ◽

pp. 383-387 ◽

Cited By ~ 10

Author(s):

Loranne Agius ◽

Barbara J. Rolls ◽

Edward A. Rowe ◽

Dermot H. Williamson

Keyword(s):

Adipose Tissue ◽

Fatty Acid ◽

Brown Adipose Tissue ◽

White Adipose Tissue ◽

Fatty Acid Synthesis ◽

Acid Synthesis ◽

High Energy ◽

Brown Adipose

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Fatty acid synthesis in brown adipose tissue of cold-acclimated mice and golden hamsters (Mesocricetus auratus)

Biochemical Society Transactions ◽

10.1042/bst0080375 ◽

1980 ◽

Vol 8 (3) ◽

pp. 375-375 ◽

Cited By ~ 2

Author(s):

P. TRAYHURN

Keyword(s):

Adipose Tissue ◽

Fatty Acid ◽

Brown Adipose Tissue ◽

Fatty Acid Synthesis ◽

Acid Synthesis ◽

Mesocricetus Auratus ◽

Golden Hamsters ◽

Brown Adipose

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The regulation of fatty acid synthesis in brown adipose tissue by insulin

Progress in Lipid Research ◽

10.1016/0163-7827(82)90009-1 ◽

1982 ◽

Vol 21 (3) ◽

pp. 195-223 ◽

Cited By ~ 54

Author(s):

James G. McCormack

Keyword(s):

Adipose Tissue ◽

Fatty Acid ◽

Brown Adipose Tissue ◽

Fatty Acid Synthesis ◽

Acid Synthesis ◽

Brown Adipose

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

Biochemical Journal ◽

10.1042/bj2120393 ◽

1983 ◽

Vol 212 (2) ◽

pp. 393-398 ◽

Cited By ~ 33

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.

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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

Bioscience Reports ◽

10.1007/bf01117517 ◽

1989 ◽

Vol 9 (1) ◽

pp. 111-117 ◽

Cited By ~ 1

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.

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