The Effects of Thyroxine and Isopropylnoradrenaline on Cytochrome Oxidase Activity in Brown Adipose Tissue

1973 ◽  
Vol 51 (10) ◽  
pp. 751-758 ◽  
Author(s):  
H. M. C. Heick ◽  
C. Vachon ◽  
Mary Ann Kallai ◽  
Nicole Bégin-Heick ◽  
J. LeBlanc

Groups of animals were treated with injections of isopropylnoradrenaline, thyroxine, or both hormones together. The effects of these hormonal treatments on the size, protein content, and level of some mitochondrial enzymes, in particular the cytochrome oxidase, were determined and compared to the effect on these parameters produced by cold adaptation. The changes observed were correlated with the resistance of the animals to cold stress and with their metabolic response to injections of isopropylnoradrenaline. All treatments increased the size of the brown adipose tissue. Whereas thyroxine had little effect on the protein content and cytochrome oxidase, both isopropylnoradrenaline and cold adaptation produced increases in these parameters. It appears that the isopropylnoradrenaline-treated animals mimic more closely the cold-adapted animals than do those with thyroxine treatment. However, the isopropylnoradrenaline-treated animals are not as resistant to cold as the cold-adapted animals.

1971 ◽  
Vol 49 (6) ◽  
pp. 545-553 ◽  
Author(s):  
Jean Himms–Hagen

The aim of these experiments was to depress the increased metabolic activity of the brown adipose tissue in the intact rat during acclimation to cold in order to elucidate further the possible thermogenic and endocrine functions of this tissue. The antibiotic oxytetracycline was administered twice daily for 2 weeks to rats living at 4 °C in an attempt to inhibit the proliferation of mitochondria and of mitochondrial inner membrane known to occur in the brown adipose tissue in response to cold; control rats received saline during the same period. Total cytochrome oxidase activity served as an index of the amount of mitochondrial inner membrane in brown adipose tissue, liver, and skeletal muscle. The development of an enhanced calorigenic response to intravenously infused noradrenaline served as an index of the extent of acclimation to cold.Treatment with oxytetracycline inhibited both the cold-induced increase in cytochrome oxidase activity in brown adipose tissue and the cold-induced development of an enhanced calorigenic response to noradrenaline in the intact rats; a direct correlation was noted between the amount of cytochrome oxidase in brown adipose tissue and the size of the metabolic response to noradrenaline of the intact animals. However, the amount of oxygen that could be consumed by the total cytochrome oxidase in the brown adipose tissue was itself too small to account for the increase in oxygen consumption by the rat. Treatment of the rats with oxytetracycline did not alter the cold-induced growth of brown adipose tissue (as judged by the increase in wet weight and the increase in total protein); it also did not alter the cytochrome oxidase activities of liver or skeletal muscle. The effect of oxytetracycline seems, therefore, to be fairly specific for the mitochondria of the most rapidly dividing tissue, the brown adipose tissue. The conclusion is drawn that a protein synthesized in the mitochondria of the brown adipose tissue in response to cold is essential for adaptation to cold.


1993 ◽  
Vol 265 (6) ◽  
pp. C1674-C1680 ◽  
Author(s):  
C. Atgie ◽  
A. Marette ◽  
M. Desautels ◽  
O. Tulp ◽  
L. J. Bukowiecki

The metabolic properties of brown adipose tissue (BAT), liver, and skeletal muscles were compared in lean and obese diabetic SHR/N-cp rats (a new model of type II diabetes) to test whether the severe insulin resistance of obese animals is specifically associated with a thermogenic defect in BAT. The respiratory response of brown adipocytes to norepinephrine and to agents bypassing the adenylate cyclase complex (dibutyryl cyclic AMP and palmitate) was decreased by two-thirds in obese rats, thereby indicating the presence of a major postreceptor defect. Significantly, total BAT cytochrome oxidase activity, uncoupling protein content, and mitochondrial guanosine 5'-diphosphate binding (3 indexes of BAT thermogenic capacity) were also decreased by two-thirds. The specific activities of these parameters expressed per total BAT mitochondrial protein were not altered either. This indicates that the total number of mitochondria per cell is decreased in BAT of obese rats. In contrast, total tissue cytochrome oxidase activity, protein content, and DNA content all increased by two to three times in the liver of obese SHR/N-cp rats, but these parameters remained unchanged in skeletal muscles (vastus lateralis and soleus). Such a remarkable liver hypertrophy may have occurred as a consequence of the persistent hyperphagia-hyperinsulinemia of obese rats that induced a hyperplasia and/or a hepatocyte polyploidization. This observation together with the fact that daily energy expenditure associated with food intake was markedly increased in obese rats (representing as much as 25% of the total energy expenditure) strongly suggests that the liver plays a major role in energy balance in these animals.(ABSTRACT TRUNCATED AT 250 WORDS)


1984 ◽  
Vol 247 (6) ◽  
pp. E800-E807
Author(s):  
J. Triandafillou ◽  
W. Hellenbrand ◽  
J. Himms-Hagen

Hamsters with muscular dystrophy (BIO 14.6) have a smaller than normal amount of brown adipose tissue. Two stimuli that promote growth of brown adipose tissue in normal hamsters, short photoperiod and eating a high-fat diet, are here shown to be without effect on brown adipose tissue of myopathic hamsters. Cold-induced growth of brown adipose tissue occurs normally [Am. J. Physiol. 239 (Cell Physiol. 8): C18–C22, 1980]. There is a normal rate of turnover of norepinephrine in brown adipose tissue of the myopathic hamster but a failure of the tissue to hypertrophy in response to norepinephrine is unlikely since norepinephrine does not appear to mediate the trophic response [Am. J. Physiol. 247 (Endocrinol. Metab. 10): E793–E799, 1984]. Denervation results in a marked reduction in size (protein content) of brown adipose tissue of normal hamsters but has very little effect on the size of brown adipose tissue of myopathic hamsters. A central, possibly hypothalamic, defect in the myopathic hamster is postulated to underlie its abnormal control of brown adipose tissue hypertrophy.


Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2752
Author(s):  
Kelsey A. Heenan ◽  
Andres E. Carrillo ◽  
Jacob L. Fulton ◽  
Edward J. Ryan ◽  
Jason R. Edsall ◽  
...  

Background: Brown adipose tissue (BAT) provides a minor contribution to diet-induced thermogenesis (DIT)—the metabolic response to food consumption. Increased BAT activity is generally considered beneficial for mammalian metabolism and has been associated with favorable health outcomes. The aim of the current systematic review was to explore whether nutritional factors and/or diet affect human BAT activity. Methods: We searched PubMed Central, Embase and Cochrane Library (trials) to conduct this systematic review (PROSPERO protocol: CRD42018082323). Results: We included 24 eligible papers that studied a total of 2785 participants. We found no mean differences in standardized uptake value of BAT following a single meal or after 6 weeks of L-Arginine supplementation. Resting energy expenditure (REE), however, was increased following a single meal and after supplementation of capsinoid and catechin when compared to a control condition (Z = 2.41, p = 0.02; mean difference = 102.47 (95% CI = 19.28–185.67)). Conclusions: Human BAT activity was not significantly affected by nutrition/diet. Moreover, REE was only increased in response to a single meal, but it is unlikely that this was due to increased BAT activity. BAT activity assessments in response to the chronic effect of food should be considered along with other factors such as body composition and/or environmental temperature.


1983 ◽  
Vol 214 (1) ◽  
pp. 265-268 ◽  
Author(s):  
K S Galpin ◽  
R G Henderson ◽  
W P T James ◽  
P Trayhurn

Cytochrome oxidase activity and mitochondrial GDP binding were decreased in brown adipose tissue of mice treated chronically with corticosterone. These changes occurred both in corticosterone-treated mice fed ad libitum and in treated mice pair-fed to control animals. Although the dietary stimulation of brown-adipose-tissue thermogenesis was suppressed by corticosterone, the acute response to cold was not affected.


1976 ◽  
Vol 231 (1) ◽  
pp. 153-160 ◽  
Author(s):  
T Rabi ◽  
Y Cassuto

Cold acclimation caused the following changes in the brown adipose tissue (BAT) of the hamster: the relative weight of the tissue increased, it color darkened, the multilocular structure predominated, and tissue protein content increased while fat content decreased. There was also an increase in the mitochondrial protein content. Heat acclimation had the opposite effects, i.e., the color became lighter, total and mitochondrial protein decreased, fat content increased, and tissue structure was mostly unilocular. Accordingly, cold acclimation was accompanied by increased tissue respiration in the presence of chi-glycerophosphate (chi-GP) and succinate, whereas heat acclimation reduced the respiratory activity of the tissue with these substrates. Isolated BAT mitochondria from cold-acclimated animals increased activities of chi-GP and NADH oxidase, whereas the activities of succinic and cytochrome oxidases and the amount of mitochondrial cytochromes were unchanged. The effects of heat acclimation were more pronounced: there was a decrease in the activities of chi-GP, succinic, NADH, and cytochrome oxidases, as well as in the cytochrome a and a3 content. When respiration of tissue slices on succinate was compared to the maximal potential respiration, as measured with mitochondria disrupted by freezing and thawing, it was found that the relative activity (slices vs. disrupted mitochondria) was highest in cold-acclimated animals and decreased progressively with increasing acclimation temperatures. It is suggested that the differences in the apparent activity of the mitochondria were due to changes in the conformation of the mitochondria as a result of acclimation.


1980 ◽  
Vol 239 (1) ◽  
pp. C18-C22 ◽  
Author(s):  
J. Himms-Hagen ◽  
C. Gwilliam

The size (wet weight, total protein, total cytochrome oxidase) of interscapular brown adipose tissue is reduced to about one-half of normal in the cardiomyopathic hamster (BIO 14.6). The mitochondria are normal in binding of purine nucleotides [guanosine 5'-diphosphate (GDP)] and in proportion of polypeptides in the region of 32,000, both indices of the thermogenic proton conductance pathway, and in specific activity of cytochrome oxidase. Brown adipose tissue of the cardiomyopathic hamster can grow during acclimation to 4 degrees C, but its size remains smaller than in cold-acclimated normal hamsters. Mitochondrial polypeptide composition is not altered by acclimation to cold, but a large increase in mitochondrial GDP binding occurs in both normal and cardiomyopathic hamsters. The reduced calorigenic response of cardiomyopathic hamsters to catecholamines (Horwitz, B.A., and G.E. Hanes, Proc. Soc. Exp. Biol. Med. 147: 393-395, 1974) may, at least in part, be explained by a reduction in the amount of brown adipose tissue, the major site of this response. A defect in control of growth of this tissue in the cardiomyopathic hamster is suggested.


1986 ◽  
Vol 6 (9) ◽  
pp. 805-810 ◽  
Author(s):  
P. Trayhurn ◽  
G. Jennings

The effects of fasting and refeeding on the concentration of uncoupling protein in brown adipose tissue mitochondria have been investigated in mice. Fasting mice for 48 h led to a large decrease in the total cytochrome oxidase activity of the interscapular brown fat pad. Mitochondrial GDP binding and the specific mitochondrial concentration of uncoupling protein also fell on fasting. After 24 h refeeding both GDP binding and the mitochondrial concentration of uncoupling protein were normalized, but there was no alteration in the total tissue cytochrome oxidase activity. Fasting appears to induce a selective loss of uncoupling protein from brown adipose tissue mitochondria, which is rapidly reversible on refeeding.


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