Evidence for the Mediatory Role of Brown Adipose Tissue During Nonshivering Thermogenesis in the Cold-Acclimated Mouse

1972 ◽  
Vol 50 (2) ◽  
pp. 168-170 ◽  
Author(s):  
J. S. Hayward ◽  
P. F. Davies
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
The Body ◽  
Brown Fat ◽  
Interscapular Brown Adipose Tissue ◽  
Adult Mice ◽  
Brown Adipose ◽  
Rate Of Oxygen Consumption

The increased rate of oxygen consumption by cold-acclimated, adult mice after subcutaneous injection of noradrenaline has been measured for intact individuals and for those with the arterial supply to their interscapular brown adipose tissue ligated. An immediate reduction of 40% of this calorigenic response was noted in mice thus operated. Dissection of the total brown fat of the body indicated that the interscapular deposits comprise 43% by weight of the total brown adipose tissue, which in turn forms only 1% of the body weight. Since a 40% reduction in calorigenic response to noradrenaline cannot be ascribed to the loss of an amount of brown fat constituting less than 0.5%) of the body weight, the results support the hypothesis that brown fat can mediate calorigenic responses of other tissues.

Evidence against a Mediatory Role of Brown Adipose Tissue in the Calorigenic Response of Cold-Acclimated Rats to Noradrenaline

1974 ◽  
Vol 52 (6) ◽  
pp. 1051-1062 ◽  
Author(s):  
David O. Foster
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
The Body ◽  
Albino Rats ◽  
Interscapular Brown Adipose Tissue ◽  
Unique Role ◽  
Brown Adipose ◽  
Colonic Temperature ◽  
Vascular Connections

The calorigenic response to infused noradrenaline (NA) of barbital-anesthetized, cold-acclimated, adult, gnotobiotic, albino rats tested 1 h after removal of interscapular brown adipose tissue (I.B.A.T.) was 14% lower than before surgery and 15% lower than the response of either sham-operated or non-operated rats; but 4 days later, the response of rats without I.B.A.T. was not significantly different from that of the controls. In unanesthetized rats, response to NA was also unaffected by interruption of blood flow to I.B.A.T. 1–3 days before the measurements. Since these results do not conform with previous findings of 30–60% reductions in response to NA following removal of I.B.A.T. or interference with the tissue's vascular connections, they contradict the current hypothesis that the B.A.T. of cold-acclimated rodents has a unique role as a mediator of calorigenesis in other tissues.A supplementary feature of the study was the discovery of apparent thermolability in the process by which cold-acclimated rats respond calorigenically to NA. If, during infusion of NA, colonic temperature exceeded about 41.5 °C, an apparently critical degree of hyperthermia response to the hormone during a subsequent infusion was reduced. This reduction was linearly related to the previous maximum colonic temperature over the range 41.6–42.4 °C and amounted to approximately 70% at 42.4 °C. These results indicate the necessity for monitoring the body temperatures of animals during infusion of NA, particularly in experiments in which two or more tests of response to NA are done on the same animal. Since such temperature measurements were not reported in those studies that have suggested a mediatory role of B.A.T. in calorigenesis in rodents, it is not possible to resolve the discrepancies on this basis.

Diet, lighting, and food intake affect norepinephrine turnover in dietary obesity

1987 ◽  
Vol 252 (2) ◽  
pp. R402-R408 ◽  
Author(s):  
T. Yoshida ◽  
J. S. Fisler ◽  
M. Fukushima ◽  
G. A. Bray ◽  
R. A. Schemmel
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
High Fat Diet ◽  
Brown Fat ◽  
Light Cycle ◽  
High Fat ◽  
Interscapular Brown Adipose Tissue ◽  
Norepinephrine Turnover ◽  
Brown Adipose ◽  
Dietary Obesity

The effects of dietary fat content, lighting cycle, and feeding time on norepinephrine turnover in interscapular brown adipose tissue, heart, and pancreas, and on blood 3-hydroxybutyrate, serum glucose, insulin, and corticosterone have been studied in two strains of rats that differ in their susceptibility to dietary obesity. S 5B/Pl rats, which are resistant to dietary obesity, have a more rapid turnover of norepinephrine in interscapular brown adipose tissue and heart and a greater increase in the concentration of norepinephrine in brown fat when eating a high-fat diet than do Osborne-Mendel rats, which are sensitive to fat-induced obesity. Light cycle and feeding schedule are important modulators of sympathetic activity in heart and pancreas but not in brown fat. Rats of the resistant strain also have higher blood 3-hydroxybutyrate concentrations and lower insulin and corticosterone levels than do rats of the susceptible strain. A high-fat diet increases 3-hydroxybutyrate concentrations and reduces insulin levels in both strains. These studies show, in rats eating a high-fat diet, that differences in norepinephrine turnover, particularly in brown adipose tissue, may play an important role in whether dietary obesity develops and in the manifestations of resistance to this phenomenon observed in the S 5B/Pl rat.

EFFECT OF TEMPERATURE ON METABOLIC RATES OF LIVER AND BROWN FAT HOMOGENATES

1967 ◽  
Vol 45 (11) ◽  
pp. 1763-1771 ◽  
Author(s):  
Jane C. Roberts ◽  
Robert E. Smith
Keyword(s):  
Adipose Tissue ◽  
Oxygen Consumption ◽  
Brown Adipose Tissue ◽  
Brown Fat ◽  
Effect Of Temperature ◽  
Metabolic Rates ◽  
Brown Adipose ◽  
Rate Of Oxygen Consumption ◽  
Effects Of Temperature

The effects of temperature in vitro upon metabolic rates of homogenates of brown fat and liver from control and cold-acclimated rats have been examined over the range 10–37 °C. At all temperatures, brown adipose tissue exhibits a higher rate of oxygen consumption [Formula: see text] than does liver, α-ketoglutarate being used as substrate. At 10 °C, brown adipose tissue retains a larger percentage (36–38%) of its 37 °C metabolic rate than does liver (22–24%).Q10 values and energies of activation (Ea) have been determined and compared with other data reported for these tissues. At 20 °C, breaks appear in the Arrhenius plots for liver from both control and cold-acclimated rats and also for brown fat from control rats, but not for the brown fat from cold-acclimated rats. Thus brown adipose tissue from cold-acclimated rats retains relatively higher levels of respiration at temperatures below the 20 °C breaking point than does brown fat from control rats.In view of previously reported cold-induced increases in mass, vascularity, and [Formula: see text] of brown fat, this decreased temperature sensitivity in the cold-acclimated rats appears wholly consonant with the adaptive behavior of brown fat in its role as a thermogenic effector.

scholarly journals The effect of interscapular brown adipose tissue removal on body-weight and cold response in the mouse

1982 ◽  
Vol 47 (3) ◽  
pp. 653-658 ◽  
Author(s):  
E. Connolly ◽  
R. D. Morrisey ◽  
J. A. Carnie
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Response ◽  
Interscapular Brown Adipose Tissue ◽  
Fat Extraction ◽  
Brown Adipose ◽  
Significant Difference ◽  
Weight Protein ◽  
And Control

1. The removal of the interscapular brown adipose tissue (IBAT) led to an increase in body-weight of normal, lean mice as compared to anaesthetized controls.2. No significant difference in food consumption could be detected between the two groups of mice over the period of the experiment.3. Fat extraction of the whole carcasses with chloroform: methanol showed a statistically significant increase in fat content in the animals without IBAT.4. There was no apparent failure in the operated animals to sustain core temperature when exposed to a cold stress situation (4° for 24 h).5. There was no difference in the wet weight, protein content or cytochrorne oxidase content of the dorso-cervical brown adipose tissue (DCBAT) between operated and control mice. This is indicative of a lack of proliferation of other brown adipose tissue sites in the operated mice in response to the removal of the IBAT.6. It is suggested that brown adipose tissue is implicated in dietary themiogenesis in the mouse.

Enlargement of Interscapular Brown Adipose Tissue in Growth Hormone Antagonist Transgenic and in Growth Hormone Receptor Gene-Disrupted Dwarf Mice

2003 ◽  
Vol 228 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Yuesheng Li ◽  
Joanne R. Knapp ◽  
John J. Kopchick
Keyword(s):  
Growth Hormone ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Uncoupling Protein ◽  
The Body ◽  
Northern Analysis ◽  
Interscapular Brown Adipose Tissue ◽  
Triglyceride Accumulation ◽  
Brown Adipose ◽  
Dwarf Mice

Growth hormone (GH) acts on adipose tissue by accelerating fat expenditure, preventing triglyceride accumulation, and facilitating lipid mobilization. To investigate whether GH is involved in the development and metabolism of interscapular brown adipose tissue (BAT), a site of nonshivering thermogenesis, we employed three lines of transgenic mice. Two of the lines are dwarf due to expression of a GH antagonist (GHA) or disruption of the GH receptor/binding-protein gene. A third mouse line is giant due to overexpression of a bovine GH (bGH) transgene. We have found that the body weights of those animals are proportional to their body lengths at 10 weeks of age. However, GHA dwarf mice tend to catch up with the nontransgenic (NT) littermates in body weight but not in body length at 52 weeks of age. The increase of body mass index (BMI) for GHA mice accelerates rapidly relative to controls as a function of age. We have also observed that BAT in both dwarf mouse lines but not in giant mice is enlarged in contrast to nontransgenic littermates. This enlargement occurs as a function of age. Northern analysis suggests that BAT can be a GH-responsive tissue because GHR/BP mRNAs were found there. Finally, the level of uncoupling protein-1 (UCP1) RNA was found to be higher in dwarf mice and lower in giant animals relative to controls, suggesting that GH-mediated signaling may negatively regulate UCP1 gene expression in BAT.

scholarly journals Detraining of exercise-trained rats: effects on energetic efficiency and brown adipose tissue thermogenesis

1987 ◽  
Vol 57 (3) ◽  
pp. 363-370 ◽  
Author(s):  
Jeff Arnold ◽  
Denis Richard
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Body Weight Gain ◽  
The Body ◽  
Metabolizable Energy ◽  
Treadmill Running ◽  
Energetic Efficiency ◽  
Brown Adipose ◽  
Brown Adipose Tissue Thermogenesis

1. Complete energy balance measurements were made in exercise-trained (treadmill running) rats subjected to 27 d of exercise detraining.2. The 20% difference in body-weight that existed at the end of the training period between sedentary and trained rats was negated by detraining. Detrained rats had twice the body-weight gain of their untrained controls.3. An elevation (12%) in metabolizable energy (ME) intake (relative to body-weight) was observed in detrained rats while their gross energetic efficiency was augmented by 60%.4. Energy expenditure, excluding the estimated costs of fat and protein storage, was similar for detrained and untrained rats. Complementing the latter was the finding that thermogenesis in brown adipose tissue, a known energy buffering process, was also similar.5. Elevated ME intake (relative to body-weight) largely contributed to the increased energetic efficiency of detrained rats.

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