Cold-induced changes in brown adipose tissue thermogenic capacity of immunocompetent and immunodeficient hairless mice

1994 ◽  
Vol 164 (6) ◽  
pp. 459-463 ◽  
Author(s):  
J. Houštěk ◽  
M. Holub

1987 ◽  
Vol 253 (2) ◽  
pp. E149-E157
Author(s):  
H. K. Kim ◽  
D. R. Romsos

Adrenalectomy prevents development of obesity in ob/ob mice fed high-carbohydrate stock diets partly by stimulating the low thermogenic capacity of their brown adipose tissue (BAT). Adrenalectomy, however, fails to prevent development of obesity in ob/ob mice fed a high-fat diet. Effects of adrenalectomy on BAT metabolism in ob/ob mice fed a high-fat diet were thus examined. ob/ob mice fed the high-fat diet developed gross obesity despite normal BAT metabolism, as assessed by rates of norepinephrine turnover in BAT, GDP binding to BAT mitochondria, and GDP-inhibitable, chloride-induced mitochondrial swelling. Adrenalectomy failed to arrest the development of obesity or to influence BAT metabolism in ob/ob mice fed the high-fat diet. Development of obesity in ob/ob mice fed a high-fat diet is not associated with low thermogenic capacity of BAT or with adrenal secretions, as it is in ob/ob mice fed high-carbohydrate stock diets.



1983 ◽  
Vol 245 (6) ◽  
pp. E582-E586 ◽  
Author(s):  
M. Hayashi ◽  
T. Nagasaka

Fasting-induced changes in thermogenic responses to norepinephrine (NE, 4.0 micrograms X kg-1 X min-1 iv) were studied in anesthetized rats previously cold acclimated. The rats were divided into five groups at the end of 30–40 days of cold acclimation (5 degrees C). The five groups were kept for 5 days at 25 degrees C and fed (intact fed), fasted (intact fasted), fasted with daily treatment with thyroxine (T4, 2 micrograms/kg sc), thyroidectomized and fed, or thyroidectomized and fasted. In the intact fasted group, in which the weight of brown adipose tissue decreased, NE-induced increases in oxygen consumption, colonic temperature (T col), and temperature of the interscapular brown adipose tissue (TBAT) were markedly suppressed. The two thyroidectomized groups also showed a reduction in thermogenic response. In these three groups, TBAT was lower than Tcol throughout NE infusion. In the T4-treated fasted group, fasting-induced suppression of thermogenic response to NE was largely prevented. In the intact fed and the T4-treated fasted groups, TBAT attained higher values than Tcol during NE infusion. Plasma levels of thyroid hormones were significantly lower in the intact fasted group than in the intact fed or the T4-treated fasted group. These results suggest that fasting-induced suppression of the thermogenic response to NE is largely due to the reduced thermogenic response of brown adipose tissue to NE. The lowering of the levels of the thyroid hormones induced by fasting may be one of a number of causes of the reduction in the thermogenic response of brown adipose tissue.



2019 ◽  
Vol 59 (5) ◽  
pp. 2207-2218 ◽  
Author(s):  
T. C. Peixoto ◽  
C. B. Pietrobon ◽  
I. M. Bertasso ◽  
F. A. H. Caramez ◽  
C. Calvino ◽  
...  




1985 ◽  
Vol 248 (2) ◽  
pp. E230-E235
Author(s):  
R. J. Schimmel ◽  
L. McCarthy

Hamsters consuming a “cafeteria diet” had more brown adipose tissue than did chow-fed hamsters. The growth of the brown fat depots in cafeteria-fed hamsters was accompanied by increases in tissue protein and cytochrome oxidase. To assess the thermogenic capacity of brown fat mitochondria, the binding of GDP to isolated mitochondria was measured. Mitochondrial GDP binding was not affected by feeding the cafeteria diet for 4 wk, but more prolonged cafeteria feeding for 8 wk did, however, increase the binding of GDP to isolated mitochondria. The morphology of brown adipose tissue was altered during cafeteria feeding. The brown adipose tissue of cafeteria-fed hamsters had more large unilocular cells than did the brown adipose tissue of chow-fed hamsters. In addition, the average adipocyte diameter was greater in brown adipose tissue of cafeteria-fed hamsters. These data support the presence of a dietary regulation of brown adipose tissue growth in hamsters. The growth of brown adipose tissue in hamsters eating the cafeteria diet appears to result largely from proliferation of adipocytes, as evidenced by the increases in tissue protein and cytochrome oxidase during cafeteria feeding, but some hypertrophy of the adipocytes also occurs. A dietary regulation of brown fat thermogenic capacity is also apparent but this regulation is evident only after more prolonged periods of cafeteria feeding. Hamsters eating a cafeteria diet increase their caloric intake but have the same or greater body weight gain efficiency as do chow-fed animals. The absence of dietary stimulation of thermogenesis may underlie the similar efficiencies of weight gain in chow- and cafeteria-fed hamsters.



2020 ◽  
Author(s):  
Bruno Halpern ◽  
Marcio C Mancini ◽  
Caroline Mendes ◽  
Camila Maria Longo Machado ◽  
Silvana Prando ◽  
...  

Abstract Objective: Melatonin has been shown to increase brown adipose tissue (BAT) mass, which can lead to important metabolic effects, such as bodyweight reduction and glycemic improvement. However, BAT mass can only be measured invasively and. the gold standard for non-invasive measurement of BAT activity is positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro-D-glucose (18F-FDG PET). There is no study, to our knowledge, that has evaluated if melatonin influences BAT activity, measured by this imaging technique in animals. Methods: Three experimental groups of Wistar rats (control, pinealectomy, and pinealectomy replaced with melatonin) had an 18F-FDG PET performed at room temperature and after acute cold exposure. The ratio of increased BAT activity after cold exposure/room temperature was called “acute thermogenic capacity” (ATC) We also measured UCP-1 mRNA expression to correlate with the 18F-FDG PET results. Results: Pinealectomy led to reduced acute thermogenic capacity, compared with the other groups, as well as reduced UCP1 mRNA expression.Conclusion: Melatonin deficiency impairs BAT response when exposed to acute cold exposure. These results can lead to future studies of the influence of melatonin on BAT, in animals and humans, without needing an invasive evaluation of BAT.



1991 ◽  
Vol 261 (2) ◽  
pp. E257-E261
Author(s):  
S. Y. Wu ◽  
J. K. Kim ◽  
I. J. Chopra ◽  
Y. Murata ◽  
D. A. Fisher

We have recently shown that ovine fetal brown adipose tissue (BAT) contains two distinct iodothyronine 5'-monodeiodinase (5'MDI) activities, one with a high Km (type I) and another with a low Km (type II). Both activities increased to maximum levels near term (150 days gestation). BAT plays a major role in neonatal temperature regulation in lambs, and available evidence suggests that BAT 5'MDI activity is closely linked to thermogenic capacity. To better characterize the changes in 5'MDI after birth, we studied both type I and type II 5'MDI in lamb BAT from the time of birth to 30 days of postnatal age. Type I 5'MDI activity [pmol 3,5,3'-triiodothyronine (T3).mg protein-1.h-1] showed no significant changes during the first 11 days after birth [newborn (NB), 95 +/- 16; 1 day, 83 +/- 20; 3-4 days, 80 +/- 11; 10-11 days, 92 +/- 28]. Activity decreased significantly at 30 days (24 +/- 8.9, P less than 0.05). On the other hand, the type II 5'MDI activity (fmol I- released.mg protein-1.h-1) increased significantly (P less than 0.01) during the first 4 days, (NB, 348 +/- 23; 1 day, 679 +/- 37; 3-4 days, 785 +/- 199), decreased toward NB values (401 +/- 87) at 10-11 days of age, and fell to 66 +/- 31 at 30 days (P less than 0.05 vs. NB). Kinetic analysis of BAT type II thyroxine 5'MDI revealed a rise in maximum velocity from NB to 1 and 3-4 days of age without a change in the enzymatic activity Km.(ABSTRACT TRUNCATED AT 250 WORDS)



1987 ◽  
Vol 252 (3) ◽  
pp. E391-E395 ◽  
Author(s):  
I. Vatnick ◽  
R. S. Tyzbir ◽  
J. G. Welch ◽  
A. P. Hooper

Rapidly regressing perirenal brown adipose tissue (BAT) of neonatal goats was studied to correlate changes in mitochondrial metabolism and thermogenic capacity with changes in mitochondrial structure. The alpha-glycerophosphate shuttle activity of perirenal BAT mitochondria declined 60% from birth to 6 days of age. Oxygen consumption and thermogenic capacity measured by ion conductance peaked at birth and declined to low levels at 6 days. Sample electron micrographs of perirenal BAT showed intact electron-dense mitochondria with many cristae and little matrix area at 2 days. However, by 6 days the mitochondria were very relaxed with large matrix area, few cristae, and observable degradation. These results indicate that the morphological changes exhibited by rapidly regressing goat's perirenal BAT in the 1st wk postpartum are accompanied by dramatic alterations in BAT mitochondrial function.



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