Nonshivering thermogenesis in king penguin chicks. II. Effect of fasting

1991 ◽  
Vol 261 (6) ◽  
pp. R1446-R1454 ◽  
Author(s):  
C. Duchamp ◽  
H. Barre ◽  
J. L. Rouanet ◽  
A. Lanni ◽  
F. Cohen-Adad ◽  
...  
Keyword(s):  
Protein Content ◽  
Mitochondrial Protein ◽  
Respiratory Control ◽  
King Penguin ◽  
Nonshivering Thermogenesis ◽  
Protein Loss ◽  
Electron Microscopic ◽  
Muscle Mitochondria ◽  
Fat Deposits ◽  
Brown Adipose

The effect of fasting on the energy metabolism of skeletal muscle and liver was investigated in cold-acclimatized short-term fasting (STF) (3 wk) and naturally long-term fasting (LTF) (4-5 mo) king penguin chicks, both groups exhibiting nonshivering thermogenesis (NST). A comparison was made with nourished cold-acclimatized controls. In these chicks, no brown adipose tissue deposits could be found on electron-microscopic observations of fat deposits. Protein content and cytochrome oxidase (CO) activity of tissue homogenates were measured in liver and pectoralis and gastrocnemius muscles, as were protein content, CO activity, and respiration rates of mitochondria isolated from these organs. Fasting-induced protein loss affected the pectoralis more than the gastrocnemius muscle, thus preserving locomotor function. In STF chicks, specific mitochondrial protein content and specific tissue CO activity were preserved but total organ CO capacity was reduced by half in pectoralis and liver following the fall in organ mass. In LTF chicks, both specific and total CO activity were drastically reduced in muscles, whereas specific CO activity was preserved in liver. In these LTF chicks, muscle mitochondria showed an energized configuration associated with an increased area of inner membrane in gastrocnemius. A reduction of respiratory control ratio (RCR) was observed in subsarcolemmal muscle mitochondria of STF chicks, whereas intermyofibrillar and liver mitochondria kept high RCR values.(ABSTRACT TRUNCATED AT 250 WORDS)

Nonshivering thermogenesis in king penguin chicks. I. Role of skeletal muscle

1991 ◽  
Vol 261 (6) ◽  
pp. R1438-R1445 ◽  
Author(s):  
C. Duchamp ◽  
H. Barre ◽  
J. L. Rouanet ◽  
A. Lanni ◽  
F. Cohen-Adad ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Content ◽  
Respiratory Control ◽  
Oxidative Capacity ◽  
Liver Mitochondria ◽  
King Penguin ◽  
Nonshivering Thermogenesis ◽  
Brown Adipose ◽  
Tissue Homogenates ◽  
Subsarcolemmal Mitochondria

In cold-acclimatized (CA) king penguin chicks exhibiting nonshivering thermogenesis (NST), protein content and cytochrome oxidase (CO) activity of tissue homogenates were measured together with protein content, CO, and respiration rates of isolated mitochondria from skeletal muscle (gastrocnemius and pectoralis) and liver. The comparison was made with chicks reared at thermoneutrality (TN) for at least 3 wk. In CA chicks showing a NST despite the lack of brown adipose tissue, an increase in thermogenic capacity was observed in skeletal muscle in which the oxidative capacity rose (+28% and +50% in gastrocnemius and pectoralis muscles, respectively), whereas no change occurred in the liver. Oxidative capacity of skeletal muscle increased together with the development of mitochondrial inner membrane plus cristae in muscles of CA chicks contrary to their TN littermates (+30 to +50%). Subsarcolemmal mitochondria of CA chicks had a higher protein content (+65% in gastrocnemius muscle) and higher oxidative capacities than in controls. The lower respiratory control ratio of these mitochondria might result from a low ADP phosphorylation rate. No change occurred in the intermyofibrillar fraction nor in liver mitochondria. These findings together with earlier results obtained in cold-acclimated ducklings indicate the marked and suited adaptation of skeletal muscle and in particular of subsarcolemmal mitochondria allowing them to play a role in NST.

Gender dimorphism in rat liver mitochondrial oxidative metabolism and biogenesis

2005 ◽  
Vol 289 (2) ◽  
pp. C372-C378 ◽  
Author(s):  
Roberto Justo ◽  
Jordi Boada ◽  
Margalida Frontera ◽  
Jordi Oliver ◽  
Jordi Bermúdez ◽  
...  
Keyword(s):  
Gender Differences ◽  
Protein Content ◽  
Rat Liver ◽  
Oxidative Metabolism ◽  
Mitochondrial Protein ◽  
Electron Microscopic ◽  
Gender Dimorphism ◽  
Protein Levels ◽  
Mitochondrial Fractions ◽  
Mitochondrial Oxidative Metabolism

In the present study, we have investigated gender differences in rat liver mitochondrial oxidative metabolism. Total mitochondrial population (M) as well as the heavy (M1), medium (M3), and light (M8) mitochondrial fractions obtained by means of differential centrifugation steps at 1,000, 3,000, and 8,000 g, respectively, were isolated. Electron microscopic analysis was performed and mitochondrial protein content and cardiolipin levels, mitochondrial O2 flux, ATP synthase activity, mitochondrial membrane potential, and mitochondrial transcription factor A (TFAM) protein levels were measured in each sample. Our results indicate that mitochondria from females have higher protein content and higher cardiolipin levels, greater respiratory and phosphorylative capacities, and more-energized mitochondria in respiratory state 3. Moreover, protein levels of TFAM were four times greater in females than in males. Gender differences in the aforementioned parameters were more patent in the isolated heavy M1 and M3 mitochondrial fractions. The present study demonstrates that gender-related differences in liver mitochondrial function are due mainly to a higher capacity and efficiency of substrate oxidation, likely related to greater mitochondrial machinery in females than in males, which is in accord with greater mitochondrial differentiation in females.

Artifactual uncoupling by uncoupling protein 3 in yeast mitochondria at the concentrations found in mouse and rat skeletal-muscle mitochondria

2001 ◽  
Vol 361 (1) ◽  
pp. 49-56 ◽  
Author(s):  
James A. HARPER ◽  
Jeff A. STUART ◽  
Mika B. JEKABSONS ◽  
Damien ROUSSEL ◽  
Kevin M. BRINDLE ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Uncoupling Protein ◽  
Mitochondrial Protein ◽  
Yeast Mitochondria ◽  
Rat Skeletal Muscle ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Uncoupling Protein 3 ◽  
Brown Adipose

Western blots detected uncoupling protein 3 (UCP3) in skeletal-muscle mitochondria from wild-type but not UCP3 knock-out mice. Calibration with purified recombinant UCP3 showed that mouse and rat skeletal muscle contained 0.14μg of UCP3/mg of mitochondrial protein. This very low UCP3 content is 200–700-fold less than the concentration of UCP1 in brown-adipose-tissue mitochondria from warm-adapted hamster (24–84μg of UCP1/mg of mitochondrial protein). UCP3 was present in brown-adipose-tissue mitochondria from warm-adapted rats but was undetectable in rat heart mitochondria. We expressed human UCP3 in yeast mitochondria at levels similar to, double and 7-fold those found in rodent skeletal-muscle mitochondria. Yeast mitochondria containing UCP3 were more uncoupled than empty-vector controls, particularly at concentrations that were 7-fold physiological. However, uncoupling by UCP3 was not stimulated by the known activators palmitate and superoxide; neither were they inhibited by GDP, suggesting that the observed uncoupling was a property of non-native protein. As a control, UCP1 was expressed in yeast mitochondria at similar concentrations to that of UCP3 and at up to 50% of the physiological level of UCP1. Low levels of UCP1 gave palmitate-dependent and GDP-sensitive proton conductance but higher levels of UCP1 caused an additional GDP-insensitive uncoupling artifact. We conclude that the uncoupling of yeast mitochondria by high levels of UCP3 expression is entirely an artifact and provides no evidence for any native uncoupling activity of the protein.

Metabolic adaptations in brown adipose tissue of the hamster in extreme ambient temperatures

1976 ◽  
Vol 231 (1) ◽  
pp. 153-160 ◽  
Author(s):  
T Rabi ◽  
Y Cassuto
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Protein Content ◽  
Cold Acclimation ◽  
Mitochondrial Protein ◽  
Heat Acclimation ◽  
Fat Content ◽  
Tissue Respiration ◽  
Cytochrome Oxidases ◽  
Brown Adipose

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.

The molecular and biochemical basis of nonshivering thermogenesis in an African endemic mammal, Elephantulus myurus

2007 ◽  
Vol 293 (5) ◽  
pp. R2120-R2127 ◽  
Author(s):  
Nomakwezi Mzilikazi ◽  
Martin Jastroch ◽  
Carola W. Meyer ◽  
Martin Klingenspor
Keyword(s):  
Cold Acclimation ◽  
Metabolic Response ◽  
Uncoupling Protein ◽  
Mammalian Species ◽  
Liver Mitochondria ◽  
Nonshivering Thermogenesis ◽  
Vertebrate Lineage ◽  
Biochemical Basis ◽  
Fat Deposits ◽  
Brown Adipose

Uncoupling protein 1 (UCP1) mediated nonshivering thermogenesis (NST) in brown adipose tissue (BAT) is an important avenue of thermoregulatory heat production in many mammalian species. Until recently, UCP1 was thought to occur exclusively in eutherians. In the light of the recent finding that UCP1 is already present in fish, it is of interest to investigate when UCP1 gained a thermogenic function in the vertebrate lineage. We elucidated the basis of NST in the rock elephant shrew, Elephantulus myurus (Afrotheria: Macroscelidea). We sequenced Ucp1 and detected Ucp1 mRNA and protein restricted to brown fat deposits. We found that cytochrome c oxidase activity was highest in these deposits when compared with liver and skeletal muscle. Consistent with a thermogenic function of UCP1 isolated BAT mitochondria showed increased state 4 respiration in the cold, as well as palmitate-induced, GDP-sensitive proton conductance, which was absent in liver mitochondria. On the whole animal level, evidence of thermogenic function was further corroborated by an increased metabolic response to norepinephrine (NE) injection. Cold acclimation (18°C) led to an increased basal metabolic rate relative to warm acclimation (28°C) in E. myurus, but there was no evidence of additional recruitment of NE-induced NST capacity in response to cold acclimation. In summary, we showed that BAT and functional UCP1 are already present in a member of the Afrotheria, but the seasonal regulation and adaptive value of NST in Afrotherians remain to be elucidated.

scholarly journals Thermogenic and lipogenic activities in brown adipose tissue of I-strain mice

1985 ◽  
Vol 231 (3) ◽  
pp. 761-764 ◽  
Author(s):  
R Bazin ◽  
D Ricquier ◽  
F Dupuy ◽  
J Hoover-Plow ◽  
M Lavau
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Protein Content ◽  
Uncoupling Protein ◽  
Mitochondrial Protein ◽  
Fatty Acid Synthetase ◽  
Food Utilization ◽  
Lower Efficiency ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose

The thermogenic capacity of brown adipose tissue has been investigated in I-strain mice to determine whether this tissue could play a role in the lower efficiency of food utilization reported in this strain of mice. (1) As compared with C57BL mice (a control strain), interscapular-brown-adipose-tissue weight and lipid percentage were decreased by 40% and 13% respectively in I-strain mice. (2) Mitochondrial protein content and cytochrome c oxidase activity were similar in the two strains, but the number of mitochondrial GDP-binding sites and uncoupling-protein content were increased by 2-fold in I-strain mice. (3) Fatty acid synthetase and citrate-cleavage enzyme (units/mg of protein) were 3-fold higher in the brown adipose tissue of I-strain mice. These results indicate that I-strain mice possess a very active brown adipose tissue. This enhanced capacity of energy dissipation in brown adipose tissue could contribute to the decreased capacity of I-strain mice to store adipose tissue.

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

1990 ◽  
Vol 258 (2) ◽  
pp. R418-R424 ◽  
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)

The role of insulin in nonshivering thermogenesis

1987 ◽  
Vol 65 (2) ◽  
pp. 152-158 ◽  
Author(s):  
Hiroyuki Shibata ◽  
Fleurette Pérusse ◽  
Ludwik J. Bukowiecki
Keyword(s):  
Mitochondrial Protein ◽  
High Capacity ◽  
Diabetic Rats ◽  
Open Circuit ◽  
Nonshivering Thermogenesis ◽  
Brown Adipose ◽  
Weight Protein ◽  
Colonic Temperature ◽  
Acute Injection ◽  
Maximal Capacity

The regulation of nonshivering thermogenesis by insulin was studied in cold-acclimated rats (2 weeks at 5 °C) made diabetic after injection with streptozotocin (75 mg/kg, i.p.) and maintained in the warm (25 °C) for 2–7 days. To investigate whether thermogenesis was activated in brown adipose tissue (BAT) of diabetic rats under physiological conditions, conscious rats were briefly exposed to cold (2 h at 5 °C) and the temperature of interscapular BAT (Tbat) was compared with the colonic temperature (Tcol). It was found that Tbat, Tcol, and Tbat – Tcot (an index of thermogenesis activation in BAT) were significantly reduced in 7-day diabetic rats (P < 0.01) but not in 2-day diabetic animals, suggesting that diabetes progressively decreases BAT thermogenic capacity. To further assess whether the maximal capacity of BAT for nonshivering themiogenesis was affected by the lack of insulin, the calorigenic response to noradrenaline (0.4 mg/kg, i.m.) was determined at 25 °C in anesthetized animals using an open circuit respirometer. The results showed that the calorigenic response to noradrenaline was inhibited by 50 and 70% in 2- and 7-day diabetic rats, respectively. Significantly, tissue weight, protein content, and cytochrome oxidase activity of interscapular BAT were also decreased by 30–40% and 50–70% in the same animals. Insulin treatment of 3-day diabetic rats for 4 days (6.5 U/day per rat) restored their calorigenic response to noradrenaline to control levels. However, this parameter was not altered by an acute injection of insulin (0.5 U/kg). It is concluded that the maximal capacity of BAT for thermogenesis is rapidly inhibited by diabetes. Insulin is not directly involved in the activation of BAT thermogenesis but is essential for the maintenance of a high capacity for nonshivering thermogenesis. Insulin may regulate BAT respiratory capacity by playing a permissive role in the control of mitochondrial protein synthesis.

Respiration and oxidative phosphorylation by mitochondria of red and white skeletal muscle

1970 ◽  
Vol 48 (1) ◽  
pp. 27-32 ◽  
Author(s):  
M. Yolanda Alvarado Rigault ◽  
M. C. Blanchaer
Keyword(s):  
Skeletal Muscle ◽  
White Muscle ◽  
Mitochondrial Protein ◽  
Respiratory Control ◽  
Carbohydrate Utilization ◽  
Muscle Mitochondria ◽  
Permeability Characteristics ◽  
Red Muscle ◽  
Muscle Types

Mitochondria from red and white skeletal muscle of the rabbit were compared polarographically with pyruvate–malate, α-glycerophosphate, and NADH as substrates. With pyruvate–malate, the organelles from the two muscle types did not differ in O2 uptake rate ([Formula: see text] mitochondrial protein per minute at 28°) or in ADP/O ratios [Formula: see text]. However, the respiratory control ratios (r.c.r.) were significantly higher in white than in red muscle mitochondria: 5.5 ± 0.3 versus 4.4 ± 0.2 (mean ± s.e.), respectively. The respiration of the white muscle mitochondria with α-glycerophosphate was similar to that with pyruvate–malate and exhibited ADP/O and r.c.r. values of 1.5 ± 0.1 and 3.0 ± 0.1, respectively. The corresponding values for red muscle mitochondria were all lower with this substrate. The organelles from both tissues were uncoupled with NADH as substrate and yielded O2 rates of less than 5% of those with pyruvate–malate.Assuming that the in vivo permeability characteristics of the organelles resemble those described above, it can be calculated that direct penetration of glycolytically generated NADH into the mitochondria would probably be too slow for its reoxidation to occur in either muscle type at a rate compatible with aerobic carbohydrate utilization. However, the intramitochondrial portion of the α-glycerophosphate shuttle has the capacity to transport reducing equivalents to the respiratory chain at the required rate. It is as yet uncertain whether it shares this role with a malate–oxaloacetate shuttle.

Cold adaptation in guinea pig at level of isolated brown adipocyte

1986 ◽  
Vol 250 (2) ◽  
pp. C228-C235 ◽  
Author(s):  
J. Rafael ◽  
W. Fesser ◽  
D. G. Nicholls
Keyword(s):  
Guinea Pig ◽  
Cold Acclimation ◽  
Guinea Pigs ◽  
Cold Adaptation ◽  
Uncoupling Protein ◽  
Mitochondrial Protein ◽  
Respiratory Control ◽  
Cell Number ◽  
Brown Adipocyte ◽  
Brown Adipose

Isolated brown adipocytes were prepared from guinea pigs acclimated to 28 degrees C or exposed to 4-8 degrees C for periods of up to 3 wk. Cells from warm-adapted animals retained respiratory control when stimulated with norepinephrine. Cells from guinea pigs exposed to cold for 4-21 days showed a much greater respiratory response to norepinephrine due to enhanced uncoupling rather than enhanced substrate supply. After 7 days of cold acclimation, norepinephrine-stimulated respiration became uncontrolled and was limited only by the maximal respiratory capacity of the mitochondria. Three weeks of cold acclimation were accompanied by a doubling of total cell number, a doubling of the mitochondrial protein per adipocyte, and a sixfold increase in the norepinephrine-stimulated respiration per in situ mitochondrion with no change in respiratory chain capacity. The induction of norepinephrine-stimulated respiration correlated with the appearance of high-affinity purine nucleotide binding sites on the mitochondria, diagnostic of the uncoupling protein. If the results are extrapolated to the whole animal, they indicate that brown adipose tissue makes little contribution to thermogenesis in the warm-adapted guinea pig but may account for most or all the increment seen on cold adaptation.

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