Irradiation of carotid baroreceptor with low‐intensity pulsed ultrasound exerts different metabolic protection in perirenal, epididymal white adipose tissue and interscapular brown adipose tissue of obese rats

The effect of prolonged fasting on sympathetic activity was examined in rat white adipose tissue (WAT) and, for comparison purposes, in interscapular brown adipose tissue (IBAT). Preliminary experiments showed that 6-hydroxydopamine or tyramine administration to fed animals produced similar reductions in norepinephrine (NE) content of WAT and IBAT. Fasting for 48 h did not affect tissue NE content significantly, but induced a threefold increase in [3H]NE uptake by retroperitoneal and epididymal adipose tissue, contrasting with a 50% reduction in IBAT. Measured with DL-alpha-methyl-p-tyrosine, NE fractional rates of turnover were faster and calculated turnover rates were three times higher in retroperitoneal and epididymal tissue from fasted rats than in tissues from fed controls. In experiments with [3H]NE, although fractional rates did not change significantly, calculated NE turnover also increased in retroperitoneal and epididymal tissue after food deprivation. In contrast, in IBAT, NE turnover either did not change (measured with DL-alpha-methyl-p-tyrosine) or, in the experiments with [3H]NE, decreased significantly after fasting. These and other data suggest that a centrally controlled selective activation of WAT sympathetic fibers contributes to fasting lipolysis.

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Effects of sucrose, caffeine, and cola beverages on obesity, cold resistance, and adipose tissue cellularity

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1983.244.4.r500 ◽

1983 ◽

Vol 244 (4) ◽

pp. R500-R507 ◽

Cited By ~ 8

Author(s):

L. J. Bukowiecki ◽

J. Lupien ◽

N. Follea ◽

L. Jahjah

Keyword(s):

Adipose Tissue ◽

Weight Gain ◽

Brown Adipose Tissue ◽

White Adipose Tissue ◽

Cold Resistance ◽

Body Weight Gain ◽

Caffeine Intake ◽

Interscapular Brown Adipose Tissue ◽

Brown Adipose ◽

Triglyceride Content

Rats consuming Coca-Cola and Purina chow ad libitum increased their total energy intake by 50% without excess weight gain. Their resistance to cold was markedly improved. These phenomena were characterized by significant increases in interscapular brown adipose tissue weight (IBAT) (91%), cellularity (59%), triglyceride content (52%), protein content (94%), and cytochrome oxidase activity (167%). In contrast, Coca-Cola consumption did not significantly affect the cellularity or triglyceride content of parametrial white adipose tissue (PWAT), although it slightly augmented PWAT weight. The effects of Coca-Cola on cold resistance, IBAT cellularity, and composition were entirely reproduced by sucrose, but not caffeine, consumption. Although caffeine also increased IBAT cellularity and composition, it significantly decreased the rate of body weight gain, PWAT weight, and adipocyte size. Moreover, it markedly inhibited adipocyte proliferation in PWAT thereby mimicking the effects of exercise training and food restriction (Bukowiecki et al., Am. J. Physiol. 239 (Endocrinol. Metab. 2): E422-E429, 1980). It is concluded a) that sucrose and Coca-Cola consumption improve the resistance of rats to cold, most probably by increasing brown adipose tissue cellularity, and b) that moderate caffeine intake might be useful for inhibiting proliferative activity in white adipose tissue, thereby preventing obesity.

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Brown adipose tissue after ventromedial hypothalamic lesions in rats

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1985.248.1.e20 ◽

1985 ◽

Vol 248 (1) ◽

pp. E20-E25 ◽

Cited By ~ 5

Author(s):

M. Saito ◽

Y. Minokoshi ◽

T. Shimazu

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Lipid Droplets ◽

Temperature Response ◽

Sympathetic Nerves ◽

Acid Synthesis ◽

Ventromedial Hypothalamus ◽

Interscapular Brown Adipose Tissue ◽

Brown Adipose ◽

Obese Rats

The interscapular brown adipose tissue (IBAT) from obese rats with lesions of the ventromedial hypothalamus (VMH) was approximately 5 times heavier than those from controls. This hypertrophy of IBAT was associated with a marked enlargement of constituent adipocytes and their apparent transformation from multiloculated structure of lipid droplets into the uniloculated structure. The rate of fatty acid synthesis in IBAT of the obese rats was less than one-tenth of that in control rats and approximated the value in white adipose tissue (WAT) when they were starved for 24 h. When rats were fed, the synthetic rate was increased, but the lipogenic response of IBAT in the obese rats was much greater than that in controls, the extent of the response being comparable to that of WAT. The IBAT temperature rose rapidly on electrical stimulation of the sympathetic nerves to the tissue in control rats, whereas the temperature response was reduced markedly in the obese rats. It was suggested that thermogenesis in BAT was impaired in obese rats with VMH lesions by decreasing triglyceride turnover in BAT, probably due to dysfunction of the sympathetic nervous system and a consequent transformation of BAT into WAT.

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Altered sympathetic activity during development of diet-induced obesity in rat

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1983.244.3.r347 ◽

1983 ◽

Vol 244 (3) ◽

pp. R347-R355 ◽

Cited By ~ 24

Author(s):

B. E. Levin ◽

J. Triscari ◽

A. C. Sullivan

Keyword(s):

Adipose Tissue ◽

Lipid Content ◽

Sympathetic Activity ◽

Turnover Rates ◽

Sprague Dawley ◽

Interscapular Brown Adipose Tissue ◽

Diet Induced Obesity ◽

Brown Adipose ◽

Obese Rats ◽

Relative Body Weight

Sprague-Dawley rats developed diet-induced obesity (DIO) after 3 mo on a high-fat, high-sucrose diet (DIO diet), with associated increases in total body and interscapular brown adipose tissue (IBAT) lipid content. After 7 days on the DIO diet, rats had increased levels of tyrosine hydroxylase (TH; 34%), norepinephrine (NE; 34%), and NE turnover (94%; estimated by alpha-methyl-p-tyrosine inhibition of TH) in their IBAT compared with chow-fed controls. After 3 mo on the DIO diet, NE levels and/or turnover were reduced by 27–50% in aortas, hearts, and pancreata in obese rats. While IBAT NE turnover was normal, TH inhibition failed to increase the lipid content of IBAT in obese rats as it did in controls, suggesting a postsynaptic defect in basal NE-stimulated lipolysis in this thermogenically active tissue. When obese rats were switched from the DIO diet to rat chow for 3 days, NE levels remained depressed in their hearts (25%) and aortas (14%) but were increased by 36–45% in IBAT, pancreata, and white adipose tissue. NE turnover rates and/or constants were increased by 37–110% in hearts, aortas, pancreata, and IBAT of these obese rats while there were increased IBAT TH (20%) and dopamine-beta-hydroxylase (87%) activities compared with chow-fed controls. Therefore, sympathetic activity varied markedly as a function of both dietary composition and relative body weight during the development of DIO.

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Effects of high-carbohydrate diets on lipogenesis in rat interscapular brown adipose tissue

Biochemical Journal ◽

10.1042/bj2060667 ◽

1982 ◽

Vol 206 (3) ◽

pp. 667-669 ◽

Cited By ~ 2

Author(s):

P. John Weaire ◽

Tazeen F. Kanagasabai

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

White Adipose Tissue ◽

White Bread ◽

Lipogenic Enzymes ◽

Adipose Tissues ◽

Interscapular Brown Adipose Tissue ◽

High Carbohydrate ◽

Brown Adipose

Cycloplasmic preparations from brown and white adipose tissues were assayed for three lipogenic enzymes throughout a programme of starvation followed by refeeding on either a normal or a white-bread diet. In the brown adipose tissue of rats fed on a white-bread diet the three enzymes were elevated to levels significantly higher than those in white adipose tissue.

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Changes in the lipogenic response to feeding of liver, white adipose tissue and brown adipose tissue during the development of obesity in the gold-thioglucose-injected mouse

Biochemical Journal ◽

10.1042/bj2590651 ◽

1989 ◽

Vol 259 (3) ◽

pp. 651-657 ◽

Cited By ~ 16

Author(s):

G J Cooney ◽

M A Vanner ◽

J L Nicks ◽

P F Williams ◽

I D Caterson

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

White Adipose Tissue ◽

Liver Lipid ◽

Insulin Concentration ◽

Obese Mice ◽

Interscapular Brown Adipose Tissue ◽

Gold Thioglucose ◽

Brown Adipose

Lipogenic response to feeding was measured in vivo in liver, epididymal white adipose tissue (WAT) and interscapular brown adipose tissue (BAT), during the development of obesity in gold-thioglucose (GTG)-injected mice. The fatty acid synthesis after a meal was higher in all tissues of GTG-treated mice on a total-tissue basis, but the magnitude of this increase varied, depending on the tissue and the time after the initiation of obesity. Lipogenesis in BAT from GTG mice was double that of control mice for the first 2 weeks, but subsequently decreased to near control values. In WAT, lipogenesis after feeding was highest 2-4 weeks after GTG injection, and in liver, lipid synthesis in fed obese mice was greatest at 7-12 weeks after the induction of obesity. The post-prandial insulin concentration was increased after 2 weeks of obesity, and serum glucose concentration was higher in fed obese mice after 4 weeks. These results indicate that increased lipogenesis in GTG-injected mice may be due to an increase in insulin concentration after feeding and that insulin resistance (assessed by lipogenic response to insulin release) is apparent in BAT before WAT and liver.

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β-adrenergic agents increase the phosphorylation of phosphofructokinase in isolated rat epididymal white adipose tissue

Biochemical Journal ◽

10.1042/bj2320905 ◽

1985 ◽

Vol 232 (3) ◽

pp. 905-910 ◽

Cited By ~ 16

Author(s):

E M Sale ◽

R M Denton

Keyword(s):

Adipose Tissue ◽

Protein Kinase ◽

Cyclic Amp ◽

White Adipose Tissue ◽

Beta Agonist ◽

Dependent Protein Kinase ◽

Interscapular Brown Adipose Tissue ◽

Adrenergic Agents ◽

Dependent Protein ◽

Epididymal White Adipose Tissue

Pieces of rat epididymal adipose tissue were incubated in medium containing [32P]phosphate for 2 h to achieve steady-state labelling of intracellular phosphoproteins and then with or without hormones for a further 15 min. Phosphofructokinase was rapidly isolated from the tissue by use of either Blue Dextran-Sepharose chromatography or immunoprecipitation with antisera raised against phosphofructokinase purified from rat interscapular brown adipose tissue. Similar extents of incorporation of 32P into phosphofructokinase were measured by both techniques. Exposure of the tissue to adrenaline or the beta-agonist isoprenaline increased phosphorylation by about 5-fold (to about 1.4 mol of phosphate/mol of enzyme tetramer). No change in phosphorylation was detected with the alpha-agonist phenylephrine, but exposure to insulin resulted in an approx. 2-fold increase. The increased phosphorylation observed with isoprenaline was found to be associated with a decrease in the apparent Ka for fructose 2,6-bisphosphate similar to that observed on phosphorylation of phosphofructokinase purified from rat epididymal white adipose tissue with the catalytic subunit of cyclic AMP-dependent protein kinase. These results support the view [Sale & Denton (1985) Biochem. J. 232, 897-904] that an increase in cyclic AMP in adipose tissue may result in an increase in glycolysis through the phosphorylation of phosphofructokinase by cyclic AMP-dependent protein kinase.

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Angiotensin II in brown adipose tissue from young and adult Zucker obese and lean rats

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1994.266.3.e453 ◽

1994 ◽

Vol 266 (3) ◽

pp. E453-E458 ◽

Cited By ~ 5

Author(s):

L. A. Cassis

Keyword(s):

Adipose Tissue ◽

Angiotensin Ii ◽

Brown Adipose Tissue ◽

Plasma Renin ◽

Ang Ii ◽

Interscapular Brown Adipose Tissue ◽

Sympathetic Neurotransmission ◽

Brown Adipose ◽

Obese Rats ◽

And Control

Previous studies demonstrated that interscapular brown adipose tissue (ISBAT) produces angiotensin II (ANG II), which facilitates sympathetic neurotransmission (SN). ANG II content and regulation of SN were examined in young (17 days) and adult (16 wk) Zucker obese and lean rats. ANG II content in ISBAT from preobese rats was decreased compared with lean littermates. Evoked 3H overflow in ISBAT slices preloaded with [3H]NE was greater in preobese rats compared with control. ANG II increased evoked 3H overflow in ISBAT slices to a greater extent in preobese rats compared with control. [3H]NE uptake in ISBAT slices from preobese rats was decreased compared with control. In adult obese rats, plasma renin activity was decreased compared with control. ISBAT ANG II content was increased in adult obese rats compared with control. Evoked 3H overflow in ISBAT slices preloaded with [3H]NE was not different between obese and control. ANG II did not increase evoked 3H overflow in obese rats; however, ANG II increased evoked 3H overflow in lean rats. [3H]NE uptake in ISBAT slices from obese rats was decreased compared with control. These results suggest that ANG II modulation of SN activity is decreased in ISBAT from adult obese rats. In contrast, in young obese rats, increased SN activity and ANG II regulation of SN were evident in brown adipose tissue.

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

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1990.258.2.r418 ◽

1990 ◽

Vol 258 (2) ◽

pp. R418-R424 ◽

Cited By ~ 4

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)

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