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 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.

Oxidative function of brown adipose tissue of lean and obese Zucker rats

1983 ◽  
Vol 11 (6) ◽  
pp. 726-727
Author(s):  
JOHN M. FLETCHER ◽  
PAUL HAGGARTY ◽  
FINELLA FORSYTH
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Zucker Rats ◽  
Brown Adipose ◽  
Obese Zucker Rats ◽  
Oxidative Function

Metformin and brown adipose tissue thermogenetic activity in genetically obese Zucker rats

1993 ◽  
Vol 246 (1) ◽  
pp. 67-71 ◽  
Author(s):  
Juha Rouru ◽  
Kaisa Isaksson ◽  
Eriika Santti ◽  
Risto Huupponen ◽  
Markku Koulu
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Zucker Rats ◽  
Brown Adipose ◽  
Obese Zucker Rats

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.

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.

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