scholarly journals Evidence for decreased GDP binding to brown-adipose-tissue mitochondria of obese Zucker (fa/fa) rats in the very first days of life

1984 ◽  
Vol 221 (1) ◽  
pp. 241-245 ◽  
Author(s):  
R Bazin ◽  
D Eteve ◽  
M Lavau
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Binding Sites ◽  
Scatchard Analysis ◽  
Zucker Rat ◽  
Large Decrease ◽  
Sequential Order ◽  
Lean Control ◽  
Brown Adipose ◽  
Obese Zucker Rat

GDP binding to brown-adipose-tissue mitochondria of obese Zucker-rat (fa/fa) pups aged 2-14 days was significantly less than in lean control rats. Scatchard analysis in 10-day-old pups suggests that there was a large decrease in GDP-binding sites. However, a significant increase in fat content in brown adipose tissue of 2-day-old pre-obese pups raised the question of the sequential order and causal relationship between these two derangements.

Identification of two mitochondrial GDP-binding sites in rat brown adipose tissue

1983 ◽  
Vol 3 (7) ◽  
pp. 589-598 ◽  
Author(s):  
K. R. Bryant ◽  
N. J. Rothwell ◽  
M. J. Stock ◽  
D. Stribling
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Binding Sites ◽  
Dissociation Constants ◽  
Mitochondrial Protein ◽  
Scatchard Analysis ◽  
Nucleotide Binding Sites ◽  
Guanosine Diphosphate ◽  
Brown Adipose ◽  
Number Of Binding Sites

Scatchard analysis of specific guanosine-diphosphate-([3H]GDP-) binding to rat brown-adipose-tissue mitochondria revealed two distinct binding sites with apparent dissociation constants (Kd) of approximately 0.05 and 2.0 μM. Binding to both sites was insensitive to atractyloside. Reducing the pH of the binding medium from 7.1 to 6.6 caused marked reductions in the Kd of both sites, but at pH 7.6, the dissociation constants were increased about 3-fold. Acute treatment of rats with noradrenaline, 1 h before sacrifice, increased the maximum number of binding sites (Bmax, pmol/rng mitochondrial protein) of both sites and also increased the dissociation constants. The Bmax of the lower-affinity site was elevated in rats exposed to 5°C or fed a palatable cafeteria diet for 10 d, compared to control animals, with the greater changes occurring in the cold-adapted group. The high-affinity site was unaltered by cold adaptation or cafeteria feeding. These results indicate the presence of two distinct nucleotide-binding sites in brown-fat mitochondria, both of which may be involved in thermogenesis.

Beta-adrenoreceptors in rat brown adipose tissue: proportions of beta 1- and beta 2-subtypes

1985 ◽  
Vol 248 (4) ◽  
pp. E397-E402 ◽  
Author(s):  
N. J. Rothwell ◽  
M. J. Stock ◽  
D. K. Sudera
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Binding Sites ◽  
Scatchard Analysis ◽  
Single Class ◽  
Brown Adipose ◽  
Ici 118,551 ◽  
Microsomal Membranes ◽  
Beta 2 ◽  
Equilibrium Dissociation

Binding of (-)-[3H]dihydroalprenolol [( 3H]DHA) to isolated brown adipose tissue (BAT) microsomal membranes was used to estimate beta-adrenoreceptor density, and this was found to be saturable, reversible, and stereospecific. Scatchard analysis indicated a single class of binding sites of equilibrium dissociation constant 2.2 nM, with a maximum number of binding sites of 160-170 fmol/mg protein. These values were unaffected by the age or sex of the animals, and similar Kd values were obtained for binding to heart and lung membranes. The kinetically derived Kd from forward and reverse reactions was 1.4 nM for BAT. Hofstee analysis of displacement of [3H]DHA produced linear plots for propranolol but curvilinear plots for atenolol and ICI 118,551. Atenolol showed 50-fold selectivity for beta 1-receptors and ICI 118,551 50-fold selectivity for beta 2-receptors in heart, lung, and BAT membranes. These plots indicated beta 1:beta 2-receptor ratios of 59:41 for BAT and heart and 25:75 for lung. It is possible that both beta-adrenoreceptor subtypes in BAT may be involved in the activation of thermogenesis in the tissue.

scholarly journals Preliminary evaluation of β3-adrenoceptor agonist-induced 18F-FDG metabolic activity of brown adipose tissue in obese Zucker rat

2015 ◽  
Vol 42 (8) ◽  
pp. 691-694 ◽  
Author(s):  
Kimberly N. Schade ◽  
Aparna Baranwal ◽  
Christopher Liang ◽  
M. Reza Mirbolooki ◽  
Jogeshwar Mukherjee
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Metabolic Activity ◽  
Preliminary Evaluation ◽  
Zucker Rat ◽  
Adrenoceptor Agonist ◽  
Brown Adipose ◽  
Obese Zucker Rat ◽  
18F Fdg

Acute influences on the two GDP-binding sites in brown-adipose-tissue mitochondria

1984 ◽  
Vol 4 (6) ◽  
pp. 523-533 ◽  
Author(s):  
K. R. Bryant ◽  
N. J. Rothwell ◽  
M. J. Stock
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Conformational Changes ◽  
Binding Sites ◽  
Dissociation Constants ◽  
Mitochondrial Protein ◽  
Scatchard Analysis ◽  
Slight Reduction ◽  
High Affinity ◽  
Brown Adipose

Scatchard analysis of3H-guanosine diphosphate (GDP) binding to rat brown-adipose-tissue mitochondria demonstrated that binding to the high- and low-affinity sites (Kd = 0.05 and 2.0 μM) was abolished by denaturation at 100°C but non-specific binding remained constant (0.2% of free-GDP). Prior incubation of mitochondria at 37°C reduced binding to the high-affinity site, but this could be reversed by incubating samples at 0°C. Addition of palmitic acid (5–40 nmole/mg of mitochondrial protein) did not affect GDP-binding, but similar concentrations of palmitoyl CoA caused a slight reduction in the number of high-affinity sites and a significant decrease in the number of lower-affinity sites. Acute treatments known to stimulate thermogenesis in vivo (a single meal, cold exposure, or noradrenaline injection 40–80 min before sacrifice) all increased binding to both binding sites, and tended to raise the dissociation constants, whereas injection of 2-deoxy-D-glucose, which depresses metabolic rate in the rat, decreased dissociation constants of both sites and the maximum number of high-affinity sites. These data indicate that both GDP-binding sites respond rapidly to acute thermogenic stimuli, possibly due to conformational changes in the mitochondrial inner membrane, and that palmitoyl CoA may influence mitochondrial proton conductance via an association with purine nucleotide binding sites.

scholarly journals Evidence for unmasking of rat brown-adipose-tissue mitochondrial GDP-binding sites in response to acute cold exposure. Effects of washing with albumin on GDP binding

1986 ◽  
Vol 233 (3) ◽  
pp. 743-747 ◽  
Author(s):  
C L Gribskov ◽  
M F Henningfield ◽  
A G Swick ◽  
R W Swick
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Exposure ◽  
Binding Sites ◽  
Uncoupling Protein ◽  
Fold Increase ◽  
Scatchard Analysis ◽  
Mitochondrial Uncoupling ◽  
Mitochondrial Uncoupling Protein ◽  
Brown Adipose

Rats, previously acclimated to 29 degrees C, were moved into the cold (4 degrees C) for 2 h. Scatchard analysis of GDP binding to the brown-adipose-tissue mitochondria of these animals showed a 2.3-fold increase in the number of high-affinity sites and a 1.5-fold increase in the number of low-affinity sites compared with binding in animals maintained at 29 degrees C. Immunochemical determination showed no increase in the amount of mitochondrial uncoupling protein during this period. This strongly suggests an unmasking of existing GDP-binding sites before a detectable increase in synthesis of uncoupling protein can occur. Washing with albumin increased the number of GDP-binding sites of brown-adipose-tissue mitochondria from both warm-housed and cold-exposed animals to the same extent. This indicates that the effects of washing with albumin and cold exposure are independent and additive.

scholarly journals The effect of adrenalectomy on GDP binding to brown-adipose-tissue mitochondria of obese rats

1982 ◽  
Vol 208 (3) ◽  
pp. 819-822 ◽  
Author(s):  
Susan Holt ◽  
David A. York
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Binding Sites ◽  
Zucker Rats ◽  
Lean Control ◽  
Brown Adipose ◽  
Obese Rats ◽  
Number Of Binding Sites ◽  
Obese Zucker Rats

GDP binding to brown-adipose-tissue mitochondria of young obese Zucker rats (fa/fa) was significantly lower than in lean control rats, as a result of a decrease in the number of binding sites. Adrenalectomy of fa/fa rats restored GDP binding to control values. Corticosterone replacement suppressed GDP binding in adrenalectomized obese rats.

Corticosterone decreases nonshivering thermogenesis and increases lipid storage in brown adipose tissue

1995 ◽  
Vol 268 (1) ◽  
pp. R183-R191 ◽  
Author(s):  
A. M. Strack ◽  
M. J. Bradbury ◽  
M. F. Dallman
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Glucocorticoid Receptors ◽  
Uncoupling Protein ◽  
Lipid Storage ◽  
Scatchard Analysis ◽  
Nonshivering Thermogenesis ◽  
Diurnal Range ◽  
Brown Adipose ◽  
Intact Rats

Brown adipose tissue (BAT) contains glucocorticoid receptors; glucocorticoids are required for maintaining differentiated BAT in culture. These studies were performed to determine the effects of corticosterone on BAT thermogenic function and lipid storage. Rats were adrenalectomized and given subcutaneous corticosterone pellets in concentrations that maintained plasma corticosterone constant across the range of 0-20 micrograms/dl or were sham adrenalectomized. All variables were examined 5 days after surgery and corticosterone replacement. Measures of BAT function-thermogenic capacity [guanosine 5'-diphosphate (GDP) binding and uncoupling protein (UCP; a BAT-specific thermogenic protein)] and storage (BAT wet wt, protein, and DNA levels) were made. Plasma hormones (corticosterone, adrenocorticotropic hormone, insulin, 3,3',5-triiodothyronine, and thyroxine were measured. Corticosterone significantly affected BAT thermogenic measures: UCP content and binding of GDP to BAT mitochondria decreased with increasing corticosterone; GDP binding characteristics in BAT from similarly prepared rats examined by Scatchard analysis showed that maximum binding (Bmax) and dissociation constant (Kd) decreased with increasing corticosterone dose. BAT DNA was increased by adrenalectomy and maintained at intact levels with all doses of corticosterone; BAT lipid storage increased dramatically at corticosterone values higher than the daily mean level in intact rats. Histologically, the number and size of lipid droplets within BAT adipocytes increased markedly with increased corticosterone. White adipose depots were more sensitive to circulating corticosterone concentrations than were BAT depots and increased in weight at levels of corticosterone that were at or below the daily mean level of intact rats. We conclude that, within its diurnal range of concentration corticosterone acts to inhibit nonshivering thermogenesis and increase lipid storage.(ABSTRACT TRUNCATED AT 250 WORDS)

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