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.

scholarly journals Thermogenic and lipogenic activities in brown adipose tissue of I-strain mice

1985 ◽  
Vol 231 (3) ◽  
pp. 761-764 ◽  
Author(s):  
R Bazin ◽  
D Ricquier ◽  
F Dupuy ◽  
J Hoover-Plow ◽  
M Lavau
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Protein Content ◽  
Uncoupling Protein ◽  
Mitochondrial Protein ◽  
Fatty Acid Synthetase ◽  
Food Utilization ◽  
Lower Efficiency ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose

The thermogenic capacity of brown adipose tissue has been investigated in I-strain mice to determine whether this tissue could play a role in the lower efficiency of food utilization reported in this strain of mice. (1) As compared with C57BL mice (a control strain), interscapular-brown-adipose-tissue weight and lipid percentage were decreased by 40% and 13% respectively in I-strain mice. (2) Mitochondrial protein content and cytochrome c oxidase activity were similar in the two strains, but the number of mitochondrial GDP-binding sites and uncoupling-protein content were increased by 2-fold in I-strain mice. (3) Fatty acid synthetase and citrate-cleavage enzyme (units/mg of protein) were 3-fold higher in the brown adipose tissue of I-strain mice. These results indicate that I-strain mice possess a very active brown adipose tissue. This enhanced capacity of energy dissipation in brown adipose tissue could contribute to the decreased capacity of I-strain mice to store adipose tissue.

Regulation of the level of uncoupling protein in brown adipose tissue by insulin

1990 ◽  
Vol 258 (2) ◽  
pp. R418-R424 ◽  
Author(s):  
A. Geloen ◽  
P. Trayhurn
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Protein Content ◽  
White Adipose Tissue ◽  
Oxidase Activity ◽  
Uncoupling Protein ◽  
Mitochondrial Protein ◽  
Brown Adipose ◽  
Epididymal White Adipose Tissue

The role of insulin in the regulation of the thermogenic activity and capacity (uncoupling protein content) of brown adipose tissue (BAT) has been investigated using mice made diabetic with streptozotocin and then subsequently infused with different doses of insulin. After 12 days of diabetes, the animals received either 0, 8, 16, or 32 units of insulin.kg body wt-1.day-1 delivered by osmotic minipumps implanted subcutaneously for 12 days. After 12 days of diabetes, body weight, interscapular BAT, and epididymal white adipose tissue weights were each reduced. In BAT, significant decreases (P less than 0.05) in the mitochondrial protein content (63%), cytochrome oxidase activity (79%), mitochondrial GDP binding (51%), and the specific mitochondrial concentration and total tissue content of uncoupling protein (71 and 89%, respectively) were obtained, indicating that the thermogenic activity and capacity of the tissue were reduced in diabetes. The infusion of insulin at a dose of 8 units.kg-1.day-1 normalized mitochondrial GDP binding and doubled the concentration of uncoupling protein. Body weight, epididymal white adipose tissue weight, and the mitochondrial protein content of BAT were restored with 16 units of insulin.kg-1.day-1. Higher doses of insulin did not further increase the specific mitochondrial concentration of uncoupling protein, but the mitochondrial content (and thereby the total uncoupling protein content) of BAT was increased and blood glucose normalized. There was a significant correlation between the dose of insulin replacement and several of the parameters measured in BAT: mitochondrial protein content (r = 0.68, P less than 0.001), cytochrome oxidase activity (r = 0.54, P less than 0.001), and total uncoupling protein content (r = 0.68, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of cortisone on brown adipose tissue of young rats

1969 ◽  
Vol 47 (12) ◽  
pp. 975-980 ◽  
Author(s):  
P. Hahn ◽  
Z. Drahota ◽  
J. Skala ◽  
S. Kazda ◽  
Molly E. Towell
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Protein Content ◽  
Reductase Activity ◽  
Fat Content ◽  
Cortisone Acetate ◽  
Young Rats ◽  
Brown Adipose

Rats aged 7 to 9 days were injected for 1 to 3 days with 5 mg/100 g body weight cortisone acetate per day. This led to an increase in the weight of brown adipose tissue, an increase in its fat content, and a decrease in its protein content. The content of norepinephrine in brown adipose tissue was decreased by cortisone treatment. The in vitro increase in O2 consumption following the addition of 5 μg nore-pinephrine/ml in vitro to brown adipose tissue from control animals was abolished by cortisone administration. Lipolysis due to norepinephrine was, however, not affected and was even slightly increased in cortisone-treated rats. Mitochondrial succinate–tetrazolium reductase activity was decreased after treatment with cortisone. It is concluded that cortisone alters the mitochondria of brown adipose tissue but has little effect on lipolysis as such. The content of norepinephrine in brown adipose tissue was found to decrease immediately after birth and then to return rapidly to higher levels.

Metabolic activity of brown adipose tissue in T3-treated hamsters

1976 ◽  
Vol 231 (1) ◽  
pp. 161-163 ◽  
Author(s):  
T Rabi ◽  
Y Cassuto
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Acclimation ◽  
Conformational Changes ◽  
Respiratory Activity ◽  
Tissue Slices ◽  
Isolated Mitochondria ◽  
Cytochrome Oxidases ◽  
Transport Chain ◽  
Brown Adipose

Triiodothyronine (T3) treatment induced marked hypertrophy of the brown adipose tissue (BAT), similar to that observed in cold-acclimated animals, although partly due to fat deposition. Similar to cold acclimation, T3 treatment also increased the oxidation of succinate by tissue slices without concomitant increase in isolated mitochondria. It is therefore suggested that thyroid hormones, like cold acclimation, effect conformational changes in the mitochondria, leading to greater expression of the succinic oxidase in the tissue. T3 treatment was not followed by any change in the respiratory activity of tissue slices in the presence of alpha-GP. Likewise, no change was found either in other oxidative activities tested in isolated mitochondria (e.g., NADH and cytochrome oxidases) or in the concentration of the components of the electron transport chain in the mitochondria.

The Effects of Thyroxine and Isopropylnoradrenaline on Cytochrome Oxidase Activity in Brown Adipose Tissue

1973 ◽  
Vol 51 (10) ◽  
pp. 751-758 ◽  
Author(s):  
H. M. C. Heick ◽  
C. Vachon ◽  
Mary Ann Kallai ◽  
Nicole Bégin-Heick ◽  
J. LeBlanc
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Protein Content ◽  
Cytochrome Oxidase ◽  
Cold Adaptation ◽  
Metabolic Response ◽  
Mitochondrial Enzymes ◽  
Cold Adapted ◽  
Brown Adipose ◽  
Hormonal Treatments

Groups of animals were treated with injections of isopropylnoradrenaline, thyroxine, or both hormones together. The effects of these hormonal treatments on the size, protein content, and level of some mitochondrial enzymes, in particular the cytochrome oxidase, were determined and compared to the effect on these parameters produced by cold adaptation. The changes observed were correlated with the resistance of the animals to cold stress and with their metabolic response to injections of isopropylnoradrenaline. All treatments increased the size of the brown adipose tissue. Whereas thyroxine had little effect on the protein content and cytochrome oxidase, both isopropylnoradrenaline and cold adaptation produced increases in these parameters. It appears that the isopropylnoradrenaline-treated animals mimic more closely the cold-adapted animals than do those with thyroxine treatment. However, the isopropylnoradrenaline-treated animals are not as resistant to cold as the cold-adapted animals.

Control of brown adipose tissue lipolysis and respiration by adenosine

1983 ◽  
Vol 245 (6) ◽  
pp. E555-E559 ◽  
Author(s):  
D. Szillat ◽  
L. J. Bukowiecki
Keyword(s):  
Adipose Tissue ◽  
Cyclic Amp ◽  
Palmitic Acid ◽  
Brown Adipose Tissue ◽  
Brown Adipocyte ◽  
Tissue Respiration ◽  
Dibutyryl Cyclic Amp ◽  
Response Curves ◽  
Brown Adipose ◽  
Stimulation Of

Adenosine competitively inhibited the stimulatory effects of (-)-isoproterenol on lipolysis and respiration in hamster brown adipocytes. The low value of the apparent ki for respiratory inhibition by adenosine (7 nM) indicated that the nucleoside may control brown adipocyte function under physiological concentrations. Significantly, the dose-response curves for isoproterenol stimulation of lipolysis and respiration were both shifted by adenosine to higher agonist concentrations by the same order of magnitude, providing additional evidence for a tight coupling between lipolysis and respiration. The inhibitory effects of adenosine were rapidly reversed by a) adenosine deaminase, b) agents known to increase intracellular cyclic AMP levels (isoproterenol, isobutylmethylxanthine, dibutyryl cyclic AMP), and c) direct stimulation of respiration with palmitic acid. These results, combined with the fact that adenosine failed to affect respiration evoked either by dibutyryl cyclic AMP or by palmitic acid, strongly indicate that adenosine regulates brown adipose tissue respiration at an early metabolic step of the stimulus-thermogenesis sequence, most probably at the level of the adenylate cyclase complex.

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
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