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

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.

1964 ◽  
Vol 206 (1) ◽  
pp. 143-148 ◽  
Author(s):  
Robert E. Smith ◽  
Jane C. Roberts

Multilocular brown adipose tissue in the rat is shown to increase in both mass and respiratory rate, in vitro, during cold acclimation. By vascular convection the resulting heat is directly applied to the thoracocervical regions of the spinal cord, the heart, and other thoracic organs. The vasculature is so arranged as to exercise a fine order of thermogenic control over the brown fat and temperature of the peripheral venous returns to the thorax, facilitated in part by a "reverse" type of countercurrent heat exchange apparently not previously described.


1968 ◽  
Vol 46 (6) ◽  
pp. 897-902 ◽  
Author(s):  
Barbara A. Horwitz ◽  
Paul A. Herd ◽  
Robert Emrie Smith

Examination of the in vivo effect of 2,4-dinitrophenol (DNP) on the brown adipose tissue of cold-exposed rats, as well as the in vitro response of this tissue to DNP and dicumarol, indicates that brown fat does possess a functional electron transport coupled phosphorylating system. Moreover, the fact that a norepinephrine-induced thermogenic response (in vivo) can be elicited from the brown fat after DNP administration implies that the effect of norepinephrine (NE) is not primarily due either to a physiological uncoupling by fatty acids, the level of which is increased by NE, or to stimulation of an ATP-ase system. Alternatively, our data suggest that under basal conditions (i.e. when the animal is not stimulated by cold stress or NE), the heat production (oxygen consumption) of the brown fat is limited by the availability of substrate rather than ADP. It is thus proposed that the thermogenic effect of NE results from the stimulation of lipolysis and an attendant increase of substrate available for oxidation.


2018 ◽  
Vol 20 (9) ◽  
pp. 2264-2273 ◽  
Author(s):  
Peter Breining ◽  
Jonas B. Jensen ◽  
Elias I. Sundelin ◽  
Lars C. Gormsen ◽  
Steen Jakobsen ◽  
...  

1972 ◽  
Vol 50 (2) ◽  
pp. 168-170 ◽  
Author(s):  
J. S. Hayward ◽  
P. F. Davies

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.


eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Haiying Zhou ◽  
Bo Wan ◽  
Ivan Grubisic ◽  
Tommy Kaplan ◽  
Robert Tjian

Brown adipose tissue (BAT) plays an essential role in metabolic homeostasis by dissipating energy via thermogenesis through uncoupling protein 1 (UCP1). Previously, we reported that the TATA-binding protein associated factor 7L (TAF7L) is an important regulator of white adipose tissue (WAT) differentiation. In this study, we show that TAF7L also serves as a molecular switch between brown fat and muscle lineages in vivo and in vitro. In adipose tissue, TAF7L-containing TFIID complexes associate with PPARγ to mediate DNA looping between distal enhancers and core promoter elements. Our findings suggest that the presence of the tissue-specific TAF7L subunit in TFIID functions to promote long-range chromatin interactions during BAT lineage specification.


1995 ◽  
Vol 20 (6) ◽  
pp. 477-484 ◽  
Author(s):  
Akihiro Kuroshima ◽  
Tomie Ohno ◽  
Mitsuru Moriya ◽  
Hiroshi Ohinata ◽  
Takehiro Yahata ◽  
...  

1988 ◽  
Vol 8 (5) ◽  
pp. 465-469 ◽  
Author(s):  
Gérard Mory ◽  
Myriam Gawer ◽  
Jean-Claude Kader

Chronic cold exposure of rats (9 days at 5°C) induces an alteration of the fatty acid composition of phospholipids in brown adipose tissue. The alteration is due to an increase of the unsaturation degree of these lipids. The phenomenon can be reproduced by 10−7 mole. h−1 administration of noradrenaline for 9 days in rats kept at 25°C. Thus, phospholipid alteration in brown fat of cold exposed rats is most probably a consequence of the increase of sympathetic tone which occurs in this tissue during exposure to cold.


1983 ◽  
Vol 245 (6) ◽  
pp. E582-E586 ◽  
Author(s):  
M. Hayashi ◽  
T. Nagasaka

Fasting-induced changes in thermogenic responses to norepinephrine (NE, 4.0 micrograms X kg-1 X min-1 iv) were studied in anesthetized rats previously cold acclimated. The rats were divided into five groups at the end of 30–40 days of cold acclimation (5 degrees C). The five groups were kept for 5 days at 25 degrees C and fed (intact fed), fasted (intact fasted), fasted with daily treatment with thyroxine (T4, 2 micrograms/kg sc), thyroidectomized and fed, or thyroidectomized and fasted. In the intact fasted group, in which the weight of brown adipose tissue decreased, NE-induced increases in oxygen consumption, colonic temperature (T col), and temperature of the interscapular brown adipose tissue (TBAT) were markedly suppressed. The two thyroidectomized groups also showed a reduction in thermogenic response. In these three groups, TBAT was lower than Tcol throughout NE infusion. In the T4-treated fasted group, fasting-induced suppression of thermogenic response to NE was largely prevented. In the intact fed and the T4-treated fasted groups, TBAT attained higher values than Tcol during NE infusion. Plasma levels of thyroid hormones were significantly lower in the intact fasted group than in the intact fed or the T4-treated fasted group. These results suggest that fasting-induced suppression of the thermogenic response to NE is largely due to the reduced thermogenic response of brown adipose tissue to NE. The lowering of the levels of the thyroid hormones induced by fasting may be one of a number of causes of the reduction in the thermogenic response of brown adipose tissue.


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