scholarly journals Resolution and identification of Gq/G11alpha and Gialpha/Goalpha proteins in brown adipose tissue: effect of cold acclimation

1999 ◽  
Vol 23 (2) ◽  
pp. 223-229 ◽  
Author(s):  
L Bourova ◽  
J Novotny ◽  
P Svoboda
Keyword(s):  
Adipose Tissue ◽  
Plasma Membrane ◽  
Brown Adipose Tissue ◽  
Cold Acclimation ◽  
Plasma Membranes ◽  
Brown Adipose ◽  
Guanine Nucleotide Binding ◽  
G 11 ◽  
Carboxy Terminal ◽  
Nucleotide Binding Proteins

Levels of guanine nucleotide-binding proteins G(q)alpha and G(11)alpha, which produce receptor regulation of phospholipase C, were measured immunologically in purified plasma membrane fractions of hamster brown adipose tissue (BAT). This was achieved by immunoblotting with antisera (CQ series) that identify these two polypeptides equally, following separation of the plasma membranes using SDS-PAGE in the presence of 6 M urea, i.e. conditions that can resolve G(q)alpha and G(11)alpha. The ratio of levels of G(q)alpha to G(11)alpha was 1:1. A similar approach was used for resolution and identification of G(o)1alpha and G(o)2alpha, the latter representing the prevailing form of G(o)alpha proteins in this tissue. Although clearly recognized in brain microsomes, which were used as positive controls, no detected levels of G(o)*alpha protein were noted. Using specific anti-peptide antibodies directed against the carboxy-terminal decapeptide of G(i)3alpha, this G protein was also found to be expressed in BAT tissue. Cold acclimation resulted in reduction of the plasma membrane levels of all these Galpha proteins.

Altered effect of insulin and catecholamines in brown adipose tissue of cold-acclimated rats

1979 ◽  
Vol 57 (3) ◽  
pp. 320-324 ◽  
Author(s):  
Nicole Bégin-Heick ◽  
Iris Noland ◽  
Marthe Dalpé ◽  
H. M. C. Heick
Keyword(s):  
Adipose Tissue ◽  
Plasma Membrane ◽  
Adenylate Cyclase ◽  
Brown Adipose Tissue ◽  
Cold Acclimation ◽  
Inhibitory Action ◽  
Cyclase Activity ◽  
Relative Response ◽  
Brown Adipose ◽  
Glucose Incorporation

Data are presented indicating that in brown adipose tissue (BAT) of cold-acclimated (CA), but not cold-exposed (CE) rats, there was an alteration in the relative response to catecholamines and insulin as evidenced by increased binding of alprenolol and decreased binding of insulin to plasma membrane enriched fractions. In addition, the stimulatory effect of insulin on glucose incorporation into glycogen and its inhibitory action on adenylate cyclase activity were both blunted in the CA tissues. It is proposed that shifts in the capacity of BAT to respond to catecholamines and insulin may be involved in the mechanism of cold acclimation.

scholarly journals Distribution of the integral plasma membrane glycoprotein CE9 (MRC OX-47) among rat tissues and its induction by diverse stimuli of metabolic activation

1995 ◽  
Vol 310 (2) ◽  
pp. 693-698 ◽  
Author(s):  
C L Nehme ◽  
B E Fayos ◽  
J R Bartles
Keyword(s):  
Adipose Tissue ◽  
Plasma Membrane ◽  
Brown Adipose Tissue ◽  
Plasma Membranes ◽  
Metabolic Activation ◽  
Blast Transformation ◽  
Rat Tissues ◽  
Membrane Glycoprotein ◽  
Brown Adipose ◽  
Different Tissues

We have compared the levels of the integral plasma membrane glycoprotein CE9 (MRC OX-47) in different tissues of the rat and have ascertained that the levels of CE9 protein and mRNA in selected tissues and cells exhibit moderate increases in response to diverse stimuli of metabolic activation. When normalized on the basis of total protein, the level of CE9 detected in the different tissues was found to vary over a 50-fold range. In addition, the apparent molecular mass of CE9 was observed to vary from 40 kDa to 68 kDa as a consequence of tissue-specific glycosylation. The highest level of CE9 was detected in brown adipose tissue, where the protein was found to be localized to the plasma membranes of the adipocytes. The metabolic activation of brown adipose tissue that occurs upon exposure of rats to the cold was found to be accompanied by 3.0 +/- 0.4-fold and 1.7 +/- 0.2-fold increases in the levels of CE9 mRNA and protein respectively. An intermediate level of CE9 was detected in the liver, where the protein is known to be expressed within the basolateral domain of the hepatocyte plasma membrane. The metabolic activation of hepatocytes that occurs upon administration of thyroid hormone to euthyroid rats was found to be accompanied by 2.2 +/- 0.3-fold and 1.9 +/- 0.3-fold increases in the levels of CE9 mRNA and protein respectively. A low level of CE9 was detected in the lymphoid organs, such as thymus and spleen. The metabolic activation of isolated rat splenocytes that occurs upon concanavalin A-mediated blast transformation in culture was found to be accompanied by 2.1 +/- 0.2-fold and 1.6 +/- 0.2-fold increases in the levels of CE9 mRNA and protein respectively. On the basis of these and other observations, we suggest that the level, and possibly also the localization, of the integral plasma membrane glycoprotein CE9 may be correlated in a positive fashion with metabolic activity in a diverse array of cell types.

scholarly journals The decrease in the short variant of gsalpha protein is associated with an increase in [3H]CGP12177 binding, [3H]ouabain binding and Na, K-ATPase activity in brown adipose tissue plasma membranes of cold-acclimated hamsters

1999 ◽  
Vol 22 (1) ◽  
pp. 55-64 ◽  
Author(s):  
L Bourova ◽  
J Novotn ◽  
P Svoboda
Keyword(s):  
Adipose Tissue ◽  
Plasma Membrane ◽  
Atpase Activity ◽  
Brown Adipose Tissue ◽  
Binding Sites ◽  
Plasma Membranes ◽  
Immunoblot Analysis ◽  
Ouabain Binding ◽  
Brown Adipose ◽  
Sds Page

Sucrose density gradient purified plasma membranes isolated from brown adipose tissue of cold-acclimated hamsters (4-10 weeks at 0-4 degreesC) were analysed for the content of the short (GsalphaS) and long (GsalphaL) variants of Gsalpha protein (the alpha subunit of the stimulatory G protein) and compared with the membranes isolated from control animals. The relative ratio between the two variants (GsalphaS/GsalphaL) decreased from 0.48 to 0.24 (P<0.01). This result, obtained by electrophoretic resolution of membrane proteins by standard SDS-PAGE and an immunoblot analysis with an antiserum oriented against an internal sequence of Gsalpha, was verified by resolution on urea-containing gels and an antiserum oriented against the C-terminus decapeptide of Gsalpha. Under these conditions, the GsalphaS/GsalphaL ratio was decreased from 0.41 to 0.31 (P<0.05). The total amount of both isoforms (GsalphaS plus GsalphaL) decreased to 83% (P<0.05) or 68% (P<0.01) by standard or urea SDS-PAGE respectively. These data demonstrate that cold-acclimation of hamster brown adipose tissue is associated with preferential decrease in the plasma membrane density of the short variant of the Gsalpha protein.%This decrease was paralleled by an increase in the other plasma membrane constituents, [3H]CGP12177 binding sites, [3H]ouabain binding sites and Na,K-ATPase activity to 147%, 212% and 191% respectively.

Basic fibroblast growth factor (bFGF) contributes to the enlargement of brown adipose tissue during cold acclimation

1994 ◽  
Vol 428 (3-4) ◽  
pp. 352-356 ◽  
Author(s):  
Hitoshi Yamashita ◽  
Yuzo Sato ◽  
Takako Kizaki ◽  
Shuji Oh-ishi ◽  
Jun -ichi Nagasawa ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Growth Factor ◽  
Brown Adipose Tissue ◽  
Fibroblast Growth Factor ◽  
Cold Acclimation ◽  
Basic Fibroblast Growth Factor ◽  
Fibroblast Growth ◽  
Brown Adipose

Lipid metabolism: Effects of immunosympathectomy and acclimation to cold

1968 ◽  
Vol 46 (3) ◽  
pp. 453-461 ◽  
Author(s):  
G. Steiner ◽  
E. Schönbaum ◽  
G. E. Johnson ◽  
E. A. Sellers
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Acclimation ◽  
Relative Weight ◽  
Fat Pad ◽  
Liver Lipids ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose ◽  
Glucose Recovery ◽  
Intact Rats

The effects of immunosympathectomy and acclimation to cold on the incorporation of glucose-U-14C into lipids of the interscapular brown adipose tissue, epididymal fat pad, and liver of rats have been investigated. Acclimation to cold was associated with an increase in glucose recovered in the total lipids of brown adipose tissue. These changes in glucose recovery were the same in immunosympathectomized as in intact rats. The brown adipose tissue of the two groups of cold-acclimated rats differed, however, in that this tissue in the immunosympathectomized animals was larger and had more lipid. Suggestions are raised to explain these findings. Neither immunosympathectomy nor cold acclimation produced any changes in white adipose tissue. Immunosympathectomy did not alter the liver's handling of glucose. However, cold-acclimation was associated with an increase in the relative weight of the liver and a decrease in glucose recovery in liver lipids.

Metabolic adaptations in brown adipose tissue of the hamster in extreme ambient temperatures

1976 ◽  
Vol 231 (1) ◽  
pp. 153-160 ◽  
Author(s):  
T Rabi ◽  
Y Cassuto
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Protein Content ◽  
Cold Acclimation ◽  
Mitochondrial Protein ◽  
Heat Acclimation ◽  
Fat Content ◽  
Tissue Respiration ◽  
Cytochrome Oxidases ◽  
Brown Adipose

Cold acclimation caused the following changes in the brown adipose tissue (BAT) of the hamster: the relative weight of the tissue increased, it color darkened, the multilocular structure predominated, and tissue protein content increased while fat content decreased. There was also an increase in the mitochondrial protein content. Heat acclimation had the opposite effects, i.e., the color became lighter, total and mitochondrial protein decreased, fat content increased, and tissue structure was mostly unilocular. Accordingly, cold acclimation was accompanied by increased tissue respiration in the presence of chi-glycerophosphate (chi-GP) and succinate, whereas heat acclimation reduced the respiratory activity of the tissue with these substrates. Isolated BAT mitochondria from cold-acclimated animals increased activities of chi-GP and NADH oxidase, whereas the activities of succinic and cytochrome oxidases and the amount of mitochondrial cytochromes were unchanged. The effects of heat acclimation were more pronounced: there was a decrease in the activities of chi-GP, succinic, NADH, and cytochrome oxidases, as well as in the cytochrome a and a3 content. When respiration of tissue slices on succinate was compared to the maximal potential respiration, as measured with mitochondria disrupted by freezing and thawing, it was found that the relative activity (slices vs. disrupted mitochondria) was highest in cold-acclimated animals and decreased progressively with increasing acclimation temperatures. It is suggested that the differences in the apparent activity of the mitochondria were due to changes in the conformation of the mitochondria as a result of acclimation.

Effects of cold acclimation in dystrophic hamsters: reduction of heart necrosis

1986 ◽  
Vol 250 (2) ◽  
pp. R167-R174
Author(s):  
M. Desautels ◽  
R. A. Dulos
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Acclimation ◽  
Ventricular Hypertrophy ◽  
Body Weight Gain ◽  
Calcium Content ◽  
Co2 Production ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose ◽  
Plasma Creatine Kinase

The effects of cold acclimation on brown adipose tissue, heart, and skeletal muscles were evaluated to assess if the increase in metabolic activity associated with chronic exposure to 4 degrees C had any influence on the progression of the syndrome in dystrophic hamsters. Body weight gain was much slower in dystrophic animals kept at 22 degrees C and was unaffected by cold acclimation. Rates of O2 consumption and CO2 production were similar in normal and dystrophic hamsters kept at 22 degrees C, and both were increased in cold-acclimated normal and dystrophic animals. The amount of interscapular brown adipose tissue was about one-half of normal in dystrophic hamsters kept at 22 degrees C. In response to cold acclimation, as in normal hamsters, brown adipose tissue of dystrophic hamsters grew and increased its thermogenin content by more than fourfold. However, the concentration of thermogenin in isolated mitochondria remained unchanged. Heart ventricular hypertrophy was also observed in both normal and dystrophic hamsters after cold acclimation. The number and extent of cardiac necrotic lesions were significantly reduced in cold-acclimated dystrophic animals when compared with age-matched dystrophic hamsters kept at 22 degrees C. Heart calcium content and plasma creatine kinase levels were also reduced in dystrophic hamsters after cold acclimation. However, in soleus muscles the prevalence of centronucleated fibers, an indirect cumulative index of necrosis, as well as the extent of tissue necrosis were not significantly reduced in cold-acclimated dystrophic animals. Thus cold acclimation of dystrophic hamsters appeared to reduce necrosis predominantly in the heart.

Neural influences on trophic changes in brown adipose tissue during cold acclimation

1988 ◽  
Vol 255 (6) ◽  
pp. R874-R881 ◽  
Author(s):  
I. R. Park ◽  
J. Himms-Hagen
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Acclimation ◽  
Elevated Level ◽  
Uncoupling Protein ◽  
Sympathetic Innervation ◽  
Intact Tissue ◽  
Brown Adipose ◽  
Neural Influences

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.

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