Evidence that the acute unmasking of GDP-binding sites in brown adipose tissue mitochondria is not dependent on mitochondrial swelling

1988 ◽  
Vol 66 (11) ◽  
pp. 1226-1230 ◽  
Author(s):  
Rachel E. Milner ◽  
Paul Trayhurn

The role of mitochondrial swelling in the unmasking of GDP-binding sites on brown adipose tissue mitochondria has been examined in mice. Acute cold exposure (6 °C for 1 h) led to increases in GDP binding without changes in the concentration of uncoupling protein, indicating that an unmasking of binding sites had occurred. Measurements of mitochondrial matrix volume suggested that an acute unmasking of GDP-binding sites took place without swelling of the mitochondria. In addition, the induction of a rapid preswelling of the mitochondria by incubation in KCl in the presence of valinomycin did not affect the cold-induced unmasking of GDP-binding sites. It is concluded that the acute unmasking of GDP-binding sites on uncoupling protein in brown adipose tissue is not due simply to mitochondrial swelling.

1988 ◽  
Vol 255 (6) ◽  
pp. R874-R881 ◽  
Author(s):  
I. R. Park ◽  
J. Himms-Hagen

We studied the role of the sympathetic innervation in development and maintenance of increased levels of uncoupling protein (UCP) and of thyroxine 5'-deiodinase (TD) during cold-induced growth of brown adipose tissue (BAT). Interscapular BAT was unilaterally (and in some experiments, bilaterally) denervated either before acclimation to cold (4 degrees C) for 12 days or after 14 days of a total 28-day period of acclimation to cold. BAT norepinephrine was reduced to 3-7% of the normal level in denervated BAT for up to 26 days. Denervation slowed, but did not prevent, cold-induced increases in total protein, in mitochondrial GDP binding, and in mitochondrial UCP concentration, which all reached 50% or more of the elevated level in intact tissue. In contrast, TD activity did not exceed 10% of the elevated level in intact tissue at any time. Denervation after cold acclimation resulted in a very rapid loss of TD activity, a slower and selective loss (after a lag of 1 day) of UCP, and a much slower loss of tissue protein. We conclude that the sympathetic innervation is required for an optimal trophic response of BAT to cold acclimation and for maintenance in the hypertrophied state but that other factors are also involved. Induction and maintenance of TD in BAT does need the sympathetic innervation.


1986 ◽  
Vol 251 (2) ◽  
pp. E192-E195
Author(s):  
A. G. Swick ◽  
R. W. Swick

GDP binding to brown adipose tissue (BAT) mitochondria increased more than twofold in 20 min when rats were moved from 27 to 4 degrees C. When animals housed at 4 degrees C for 2 h were returned to 27 degrees C, GDP binding decreased sharply in 20 min and returned to control levels in 2 h. These results are consistent with a rapid unmasking and remasking of GDP binding sites. GDP binding to mitochondria from warm and acutely cold treated rats was not modified by prior swelling, by freeze-thawing, nor by sonication of the mitochondria before assay. GDP-inhibitable proton conductance, as measured by passive swelling, was unaffected by this brief exposure to cold but more than doubled in rats kept at 4 degrees C for 10 days. We hypothesize that the rate of GDP-inhibitable swelling may be a reflection of uncoupling protein concentration in the BAT mitochondria, whereas physiological thermogenic activity is more appropriately indicated by GDP binding. The alterations in binding activity appear not to be due to changes in the mitochondrial membrane integrity.


Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 904 ◽  
Author(s):  
Linjie Wang ◽  
Xin Yang ◽  
Yuehua Zhu ◽  
Siyuan Zhan ◽  
Zhe Chao ◽  
...  

Long noncoding RNAs (lncRNAs) play an important role in the thermogenesis and energy storage of brown adipose tissue (BAT). However, knowledge of the cellular transition from BAT to white adipose tissue (WAT) and the potential role of lncRNAs in goat adipose tissue remains largely unknown. In this study, we analyzed the transformation from BAT to WAT using histological and uncoupling protein 1 (UCP1) gene analyses. Brown adipose tissue mainly existed within the goat perirenal fat at 1 day and there was obviously a transition from BAT to WAT from 1 day to 1 year. The RNA libraries constructed from the perirenal adipose tissues of 1 day, 30 days, and 1 year goats were sequenced. A total number of 21,232 lncRNAs from perirenal fat were identified, including 5393 intronic-lncRNAs and 3546 antisense-lncRNAs. Furthermore, a total of 548 differentially expressed lncRNAs were detected across three stages (fold change ≥ 2.0, false discovery rate (FDR) < 0.05), and six lncRNAs were validated by qPCR. Furthermore, trans analysis found lncRNAs that were transcribed close to 890 protein-coding genes. Additionally, a coexpression network suggested that 4519 lncRNAs and 5212 mRNAs were potentially in trans-regulatory relationships (r > 0.95 or r < −0.95). In addition, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that the targeted genes were involved in the biosynthesis of unsaturated fatty acids, fatty acid elongation and metabolism, the citrate cycle, oxidative phosphorylation, the mitochondrial respiratory chain complex, and AMP-activated protein kinase (AMPK) signaling pathways. The present study provides a comprehensive catalog of lncRNAs involved in the transformation from BAT to WAT and provides insight into understanding the role of lncRNAs in goat brown adipogenesis.


1989 ◽  
Vol 257 (1) ◽  
pp. E81-E87 ◽  
Author(s):  
I. R. Park ◽  
D. B. Mount ◽  
J. Himms-Hagen

Cold-induced growth of brown adipose tissue (BAT) was studied in thyroidectomized rats that received low doses of either thyroxine (T4) or 3,5,3'-triidothyronine (T3). The objective was to find out whether the cold-induced increase in activity of T4 5'-deiodinase, and thus increased endogenous T3 generation in BAT itself, was necessary for growth of BAT or whether T3 from the blood could serve as effectively as T3 produced endogenously. The acute thermogenic response of BAT to cold (15 h at 4 degrees C), as measured by the increase in mitochondrial GDP binding, was abolished by thyroidectomy, as seen previously, and restored by T3 as well as by T4 treatment. The long-term trophic response to cold (20–25 days at 4 degrees C), as indicated by increases in protein and DNA and in mitochondrial concentrations of GDP-binding sites and uncoupling protein, occurred whether T3 or T4 was administered to these thyroidectomized rats. We conclude that endogenous T3 production in BAT does not direct and is not essential for the long-term trophic response of this tissue to cold. We are not able to exclude, on the basis of the present results, that an optimal growth rate during the initial phase of the trophic response may require enhanced endogenous production of T3 in BAT. The cold-induced increase in T4 5'-deiodinase activity, presumably mediated by an action of norepinephrine, does not require the presence of either T3 or T4, as seen previously by others.


1988 ◽  
Vol 249 (3) ◽  
pp. 759-763 ◽  
Author(s):  
R E Milner ◽  
S Wilson ◽  
J R Arch ◽  
P Trayhurn

GDP binding, proton conductance and the specific concentration of uncoupling protein were measured in brown-adipose-tissue mitochondria of rats treated acutely with the novel beta-agonist, BRL 26830A. At 1 h after dosing with BRL 26830A, mitochondrial GDP binding was increased more than 2-fold. The increase in binding resulted from an increase in the number of binding sites. An iterative analysis of Scatchard binding data suggested that there is only one high-affinity GDP-binding site (Kd 0.3 microM) in brown-adipose-tissue mitochondria. The acute increase in GDP binding produced by treatment with BRL 26830A occurred without any alteration in the specific mitochondrial concentration of uncoupling protein, as determined by radioimmunoassay. Treatment with the beta-agonist did, however, lead to a small increase in the GDP-sensitive component of mitochondrial proton conductance. These results indicate that GDP-binding sites on uncoupling protein can be rapidly unmasked after treatment with a brown-fat-specific beta-agonist, and that the increase in binding reflects an increase in the activity of the mitochondrial proton-conductance pathway.


1989 ◽  
Vol 36 (4) ◽  
pp. 491-499 ◽  
Author(s):  
KEIJI YOSHIOKA ◽  
TOSHIHIDE YOSHIDA ◽  
YASUO WAKABAYASHI ◽  
HITOSHI NISHIOKA ◽  
MOTOHARU KONDO

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