Increased α1 receptor density in brown adipose tissue of cafeteria-fed rats

1984 ◽  
Vol 4 (10) ◽  
pp. 851-859 ◽  
Author(s):  
Atso Raasmaja ◽  
Nina Mohell ◽  
Jan Nedergaard
Keyword(s):  
Adipose Tissue ◽  
Plasma Membrane ◽  
Membrane Protein ◽  
Brown Adipose Tissue ◽  
Adrenergic Receptors ◽  
Brown Fat ◽  
Physiological Significance ◽  
Female Rats ◽  
Receptor Density ◽  
Brown Adipose

A possible general corollary between α1-receptor density in brown adipose tissue and the degree of activation of the tissue was investigated. For this purpose, the effect of cafeteria feeding on α1-adrenergic receptors in brown adipose tissue of seven-week-old female rats was studied by the use of the α1-antagonist (3H)prazosin. In cafeteria-fed rats, the KD of the α1-receptor for (3H)prazosin was unchanged (about 0.35 nM), but the receptor density was doubled (up to 40 fmol per mg of membrane protein). This was also observed when the results were expressed per unit of a plasma-membrane marker (5′-nucleotidase). It was concluded that an increased α1-receptor density is seen not only in cold-acclimated rats, but also in other conditions where brown fat is activated, and a possible general physiological significance of α1-adrenergic pathways in brown adipose tissue is discussed.

scholarly journals α1- and β-adrenergic receptors in brown adipose tissue of lean (Fa/?) and obese (fa/fa) Zucker rats. Effects of cold-acclimation, sucrose feeding and adrenalectomy

1988 ◽  
Vol 249 (3) ◽  
pp. 831-838 ◽  
Author(s):  
A Raasmaja ◽  
D A York
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Acclimation ◽  
Adrenergic Receptors ◽  
Zucker Rats ◽  
Receptor Density ◽  
Beta Adrenergic Receptors ◽  
Brown Adipose ◽  
Sucrose Feeding ◽  
Obese Zucker Rats

1. The populations of alpha 1- and beta-adrenergic receptors in brown adipose tissue (BAT) of genetically obese Zucker rats (fa/fa) were studied with [3H]prazosin and [3H]CGP-12177 respectively. 2. The density of alpha 1-adrenergic receptors in BAT was significantly lower in obese than in lean Zucker rats, both at 2-4 months of age and at 6 weeks of age. The density of beta-adrenergic receptors was identical in BAT of lean and obese 6-week-old Zucker rats. 3. Cold-acclimation increased the alpha 1-receptor density significantly in BAT of both lean and obese Zucker rats, and the number of beta-receptors was also somewhat increased. 4. Sucrose feeding did not affect the density of alpha 1-receptors in BAT of lean or obese Zucker rats, but it increased beta-receptor density. 5. Adrenalectomy restored the density of alpha 1-adrenergic receptors in BAT of obese Zucker rats to the value observed in lean rats. 6. It is concluded that there is a direct correlation between alpha 1-receptor density and tissue recruitment, and that alpha 1-receptor density is thus positively correlated with sympathetic activity. beta-Receptor density is apparently better correlated with feeding conditions.

Increased alpha 1-adrenoceptor density in brown adipose tissue indicates recruitment drive in hypothyroid rats

1992 ◽  
Vol 263 (4) ◽  
pp. E654-E662 ◽  
Author(s):  
A. Dicker ◽  
A. Raasmaja ◽  
B. Cannon ◽  
J. Nedergaard
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Uncoupling Protein ◽  
Whole Body ◽  
Total Protein Content ◽  
Receptor Density ◽  
Beta Adrenergic ◽  
Brown Adipose

The effects of hypothyroidism on whole body thermogenesis, brown adipose tissue recruitment state, and alpha 1-adrenergic receptor density were investigated. Treatment of rats with methimazole for 4-5 wk led, as expected, to reduction of growth and resting metabolic rate. The thermogenic response to norepinephrine injection was practically abolished. Generally, only small effects of hypothyroidism on brown adipose tissue were observed: total protein content, mitochondrial GDP binding capacity, and total content of the uncoupling protein thermogenin were not altered. The density of beta-adrenergic receptors (estimated with [3H]CGP-12177 as a ligand) was also unchanged. However, the density of alpha 1-adrenergic receptors (estimated with [3H]prazosin) was markedly increased; in other physiological conditions, such an increase has been associated with an increased degree of recruitment of the tissue. These data indicate that brown adipose tissue in the subthermoneutral hypothyroid animal, probably due to homeostatic mechanisms, is exposed to an increased sympathetic stimulation, leading to an increased alpha 1-adrenoceptor density. However, other features of recruitment are only poorly induced, probably due to attenuation of the beta-adrenergic signaling mechanism. The increased alpha 1-adrenergic receptor density may be responsible for certain altered features of brown adipose tissue in hypothyroid animals, such as peroxisomal recruitment and perhaps also for maintenance of the thermogenin content. The results also indicate that the increased alpha 1-adrenergic density generally seen in recruitment would not result from chronic beta-adrenergic stimulation of the tissue but may be controlled via another regulatory pathway, e.g., via the alpha 1-adrenergic pathway itself.

Effect of noradrenaline chronic administration on brown fat phospholipids

1988 ◽  
Vol 8 (5) ◽  
pp. 465-469 ◽  
Author(s):  
Gérard Mory ◽  
Myriam Gawer ◽  
Jean-Claude Kader
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Acid Composition ◽  
Cold Exposure ◽  
Chronic Administration ◽  
Sympathetic Tone ◽  
Brown Fat ◽  
Brown Adipose

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.

Early weaning alters the thermogenic capacity of brown adipose tissue in adult male and female rats

2019 ◽  
Vol 59 (5) ◽  
pp. 2207-2218 ◽  
Author(s):  
T. C. Peixoto ◽  
C. B. Pietrobon ◽  
I. M. Bertasso ◽  
F. A. H. Caramez ◽  
C. Calvino ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Adult Male ◽  
Female Rats ◽  
Early Weaning ◽  
Male And Female ◽  
Male And Female Rats ◽  
Brown Adipose ◽  
Thermogenic Capacity

The development of insulin resistance in brown adipose tissue may impair the acute cold-induced activation of thermogenesis in genetically obese (ob/ob) mice

1984 ◽  
Vol 4 (11) ◽  
pp. 933-940 ◽  
Author(s):  
Stewart W. Mercer ◽  
Paul Trayhurn
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Exposure ◽  
Brown Fat ◽  
Acute Cold Exposure ◽  
Brown Adipose

Genetically obese (ob/ob) mice develop insulin resistance in brown adipose tissue during the fifth week of life. Prior to this, at 26 days of age, oh/oh mice show a substantial increase in GDP binding to brownadipose-tissue mitochondria during acute cold exposure. When insulin resistance in brown fat develops, by 35 days of age, the increase in GDP binding in response to cold is markedly reduced. Studies with 2-deoxyglucose suggest that insulin resistance in brown adipose tissue could impair thermogenic responsiveness during acute cold exposure by limiting the ability of the tissue to take up glucose.

OBSERVATIONS ON PEROXISOMES IN BROWN ADIPOSE TISSUE OF THE RAT

1971 ◽  
Vol 19 (11) ◽  
pp. 670-675 ◽  
Author(s):  
IRÉNE AHLABO ◽  
TUDOR BARNARD
Keyword(s):  
Hydrogen Peroxide ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Single Unit ◽  
Brown Fat ◽  
Unit Membrane ◽  
Peroxisomal Enzyme ◽  
Brown Adipose ◽  
Homogeneous Matrix ◽  
Physiologic Activity

During cytochemical studies of brown adipose tissue from rat, cytoplasmic organelles that apparently show peroxidative activity have been observed. The majority of the organelles have a diameter of 0.1-0.8 µ and a finely granular homogeneous matrix and are delimited by a single unit membrane. No sign of a "crystalloid" was seen. In order to demonstrate the peroxidative activity of the peroxisomal enzyme catalase in the organelles, brown adipose tissue was incubated in a medium containing 3,3'-diaminobenzidine tetrahydrochloride, after prefixation in 3% glutaraldehyde. The activity was blocked by 3-amino-l,2,4-triazole (an inhibitor of catalase) but not by KCN. Omission of exogenous hydrogen peroxide did not inhibit the reaction in the organelles. It is concluded that rat brown adipose tissue contains peroxisomes and, since the abundance of these organelles varies according to the physiologic activity of the tissue, peroxisomes may have a role in the thermogenic metabolism of brown fat.

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