Effect of some hormones on the rate of the triacylglycerol/fatty-acid substrate cycle in adipose tissue of the mouse in vivo

1983 ◽  
Vol 3 (3) ◽  
pp. 263-267 ◽  
Author(s):  
B. J. Brooks ◽  
J. R. S. Arch ◽  
E. A. Newsholme
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
White Adipose Tissue ◽  
Nervous Activity ◽  
Sympathetic Nervous Activity ◽  
Fatty Acid Substrate ◽  
Brown Adipose ◽  
Adrenergic Blocker

A method is described for the measurement of the rate of the triacylglycerol/fatty-acid cycle in adipose tissue of the mouse in vivo, which depends upon the incor-poration of tritium from [3H]H2O into the glycerol and fatty-acid moieties of triacyiglycerol. The rate of the cycling is increased two-fold by feeding, an effect that is completely abolished by the β-adrenergic blocker propranolol. The β-adrenergic agonist fenoterol increased the rate of cycling five-fold in white adipose tissue and three-fold in brown adipose tissue. Cold exposure had no effect on the rate of cycling in white adipose tissue but increased the rate almost two-fold in brown adipose tissue. The increased rate of cycling during feeding, which may be due to increased sympathetic nervous activity, is consistent with the view that the role of cycling is to increase sensitivity of metabolic control systems when required.

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.

Thermogenesis after lateral hypothalamic lesions: contributions of brown adipose tissue

1988 ◽  
Vol 255 (5) ◽  
pp. E708-E715 ◽  
Author(s):  
S. W. Corbett ◽  
L. N. Kaufman ◽  
R. E. Keesey
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Nervous Activity ◽  
Male Rats ◽  
Sympathetic Nervous Activity ◽  
Primary Role ◽  
Interscapular Brown Adipose Tissue ◽  
Lateral Hypothalamic ◽  
Brown Adipose ◽  
The Hours

The role of brown adipose tissue in the thermogenic response to lateral hypothalamic (LH) lesions was investigated. Interscapular brown adipose tissue (IBAT) temperatures were measured during the hours following bilateral electrolytic LH lesions in male rats sedated with pentobarbital sodium. Local temperature changes were also recorded from skin and colonic sites. Consistent with the view that brown adipose tissue plays a primary role in the hyperthermia produced by LH lesions, IBAT depot temperature rose before, at a faster rate, and to a higher level than the other sites. In two subsequent experiments, oxygen consumption, activity, and core temperature were monitored in freely moving male rats with LH lesions, both in warm (25 degrees C) and cold (5 degrees C) environments. The results of these experiments provide some support for the view that LH lesions produce an increase in the regulated level of body temperature. This hyperthermic and hypermetabolic state seems to be mediated, in part, by brown fat thermogenesis and may represent a general increase in sympathetic nervous activity induced by the lesion.

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.

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.

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.

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