Reduced Mitochondrial Efficiency Explains Mismatched Growth and Metabolic Rate at Supraoptimal Temperatures

Metabolic activity sets the rates of individual resource uptake from the environment and resource allocations. For this reason, the relationship with body size has been heavily documented from ecosystems to cells. Until now, most of the studies used the fluxes of oxygen as a proxy of energy output without knowledge of the efficiency of biological systems to convert oxygen into ATP. The aim of this study was to examine the allometry of coupling efficiency (ATP/O) of skeletal muscle mitochondria isolated from 12 mammal species ranging from 6 g to 550 kg. Mitochondrial efficiencies were measured at different steady states of phosphorylation. The efficiencies increased sharply at higher metabolic rates. We have shown that body mass dependence of mitochondrial efficiency depends on metabolic intensity in skeletal muscles of mammals. Mitochondrial efficiency positively depends on body mass when mitochondria are close to the basal metabolic rate; however, the efficiency is independent of body mass at the maximum metabolic rate. As a result, it follows that large mammals exhibit a faster dynamic increase in ATP/O than small species when mitochondria shift from basal to maximal activities. Finally, the invariant value of maximal coupling efficiency across mammal species could partly explain why scaling exponent values are very close to 1 at maximal metabolic rates.

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Red knots (Calidris canutus islandica) manage body mass with dieting and activity

Journal of Experimental Biology ◽

10.1242/jeb.231993 ◽

2020 ◽

Vol 223 (21) ◽

pp. jeb231993

Author(s):

Kimberley J. Mathot ◽

Eva M. A. Kok ◽

Piet van den Hout ◽

Anne Dekinga ◽

Theunis Piersma

Keyword(s):

Food Intake ◽

Metabolic Rate ◽

Body Mass ◽

Assimilation Efficiency ◽

Adaptive Significance ◽

Fine Scale ◽

Calidris Canutus ◽

Predation Danger ◽

Mitochondrial Efficiency

ABSTRACTMass regulation in birds is well documented. For example, birds can increase body mass in response to lower availability and/or predictability of food and decrease body mass in response to increased predation danger. Birds also demonstrate an ability to maintain body mass across a range of food qualities. Although the adaptive significance of mass regulation has received a great deal of theoretical and empirical attention, the mechanisms by which birds achieve this have not. Several non-exclusive mechanisms could facilitate mass regulation in birds. Birds could regulate body mass by adjusting food intake (dieting), activity, baseline energetic requirements (basal metabolic rate), mitochondrial efficiency or assimilation efficiency. Here, we present the results of two experiments in captive red knots (Calidris canutus islandica) that assess three of these proposed mechanisms: dieting, activity and up- and down-regulation of metabolic rate. In the first experiment, knots were exposed to cues of predation risk that led them to exhibit presumably adaptive mass loss. In the second experiment, knots maintained constant body mass despite being fed alternating high- and low-quality diets. In both experiments, regulation of body mass was achieved through a combination of changes in food intake and activity. Both experiments also provide some evidence for a role of metabolic adjustments. Taken together, these two experiments demonstrate that fine-scale management of body mass in knots is achieved through multiple mechanisms acting simultaneously.

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Development of new predictive equations for basal metabolic rate in Iranian healthy adults: negligible effect of sex

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000669 ◽

2020 ◽

pp. 1-10

Author(s):

Bahareh Nikooyeh ◽

Nastaran Shariatzadeh ◽

Ali Kalayi ◽

Maliheh Zahedirad ◽

Tirang R. Neyestani

Keyword(s):

Metabolic Rate ◽

Thyroid Function ◽

Basal Metabolic Rate ◽

Age Groups ◽

Thyroid Function Tests ◽

Anthropometric Measures ◽

Predictive Equations ◽

Normal Thyroid Function ◽

Asian People ◽

Predictive Formulas

Abstract. Some studies have reported inaccuracy of predicting basal metabolic rate (BMR) by using common equations for Asian people. Thus, this study was undertaken to develop new predictive equations for the Iranian community and also to compare their accuracy with the commonly used formulas. Anthropometric measures and thyroid function were evaluated for 267 healthy subjects (18–60 y). Indirect calorimetry (InCal) was performed only for those participants with normal thyroid function tests (n = 252). Comparison of predicted RMR (both kcal/d and kcal.kg.wt−1.d−1) using current predictive formulas and measured RMR revealed that Harris-Benedict and FAO/WHO/UNU significantly over-estimated and Mifflin-St. Jeor significantly under-estimated RMR as compared to InCal measurements. In stepwise regression analysis for developing new equations, the highest r2 (=0.89) was from a model comprising sex, height and weight. However, further analyses revealed that unlike the subjects under 30 y, the association between age and the measured RMR in subjects 30 y and plus was negative (r = −0.241, p = 0.001). As a result, two separate equations were developed for these two age groups. Over 80 percent of variations were covered by the new equations. In conclusion, there were statistical significant under- and over-estimation of RMR using common predictive equations in our subjects. Using the new equations, the accuracy of the calculated RMR increased remarkably.

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Nutrient pattern of unsaturated fatty acids and vitamin E increase resting metabolic rate of overweight and obese women

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000664 ◽

2020 ◽

pp. 1-9

Author(s):

Habib Yarizadeh ◽

Leila Setayesh ◽

Caroline Roberts ◽

Mir Saeed Yekaninejad ◽

Khadijeh Mirzaei

Keyword(s):

Vitamin E ◽

Metabolic Rate ◽

Unsaturated Fatty Acids ◽

Resting Metabolic Rate ◽

Blood Parameters ◽

Cross Sectional Study ◽

Obese Women ◽

Cross Sectional ◽

Dietary Nutrients ◽

Nutrient Patterns

Abstract. Objectives: Obesity plays an important role in the development of chronic diseases including cardiovascular disease and diabetes. A low resting metabolic rate (RMR) for a given body size and composition is a risk factor for obesity, however, there is limited evidence available regarding the association of nutrient patterns and RMR. The aim of this study was to determine the association of nutrient patterns and RMR in overweight and obese women. Study design: This cross-sectional study was conducted on 360 women who were overweight or obese. Method: Dietary intake was assessed using a semi-quantitative standard food frequency questionnaire (FFQ). Nutrient patterns were also extracted by principal components analysis (PCA). All participants were evaluated for their body composition, RMR, and blood parameters. Result: Three nutrient patterns explaining 64% of the variance in dietary nutrients consumption were identified as B-complex-mineral, antioxidant, and unsaturated fatty acid and vitamin E (USFA-vit E) respectively. Participants were categorized into two groups based on the nutrient patterns. High scores of USFA-vit E pattern was significantly associated with the increase of RMR (β = 0.13, 95% CI = 0.79 to 68.16, p = 0.04). No significant associations were found among B-complex-mineral pattern (β = −0.00, 95% CI = −49.67 to 46.03, p = 0.94) and antioxidant pattern (β = 0.03, 95% CI −41.42 to 22.59, p = 0.56) with RMR. Conclusion: Our results suggested that the “USFA-vit E” pattern (such as PUFA, oleic, linoleic, vit.E, α-tocopherol and EPA) was associated with increased RMR.

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Quantitative measurement of cerebral metabolic rate of glucose by means of dual-head coincidence gamma camera and 2-deoxy-2- [18F] fluoro-D-glucose

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/sj.jcbfm.9591524.0670 ◽

2005 ◽

Vol 25 (1_suppl) ◽

pp. S670-S670

Author(s):

Katsufumi Kajimoto ◽

Naohiko Oku ◽

Yasuyuki Kimura ◽

Makiko Tanaka ◽

Hiroki Kato ◽

...

Keyword(s):

Metabolic Rate ◽

Gamma Camera ◽

Quantitative Measurement ◽

Cerebral Metabolic Rate

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The Influence of the Thyroid Function on the Metabolic Rate of Prothrombin, Factor VII, and Factor X in the Rat

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647959 ◽

1976 ◽

Vol 35 (03) ◽

pp. 607-619 ◽

Cited By ~ 8

Author(s):

Allan T. van Oosterom ◽

Herman Mattie ◽

Wim Th Hermens ◽

Jan J. Veltkamp

Keyword(s):

Metabolic Rate ◽

Thyroid Function ◽

Coagulation Factors ◽

Biologically Active ◽

Factor Vii ◽

Synthesis Rate ◽

Apparent Difference ◽

Vitamin K1 ◽

Factor X ◽

Significant Difference

SummaryThe influence of the thyroid function on the metabolic rate of prothrombin, factor VII, and X was studied in the rat. Disappearance rates of the three coagulation factors were measured after synthesis had been blocked with appropriate doses of warfarin, and reappearance rates were assessed upon induction of synthesis by high doses of vitamin K1 injected into rats displaying coumarin induced hypocoagulability.No statistically significant difference in the disappearance and production rates of any of the factors could be found between normal euthyroid rats and thyroxin-treated hypothyroid rats proven to be euthyroid. The differences between the two euthyroid groups and the hypothyroid group were highly significant, however: hypothyroidism results in an approximately 50% decrease of the metabolic rates of the three coagulation factors under study.The reappearance of the three factors, under euthyroid as well as hypothyroid conditions, showed a biphasic pattern: in the first two hours after vitamin K1 administration to warfarin treated rats, a rapid reappearance was observed, to the same extent for all three factors, in hypo- as well as euthyroid rats. This finding suggests that in vitamin K1 deficiency an intracellular accumulation of precursor proteins (PIVKAs) occurs, which after rapid conversion into biologically active coagulation factors by vitamin K1 are shed into circulation.The subsequent phase of reappearance is much slower and reflects the synthesis rate of coagulation enzymes. It is characteristic for each factor and clearly slower in hypothyroid rats than in euthyroid rats. From this an influence of thyroid function on the synthesis rate of the protein moiety of coagulation factors can be inferred.An apparent difference between disappearance and reappearance rate of the coagulation factors in the plasma, particularly pronounced for factors VII and X in euthyroid rats, could theoretically be explained as the consequence of the model used for derivation of these rates.

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Estimation of the in vivo metabolic rate of adipose tissue in obese mice

Aktuelle Ernährungsmedizin ◽

10.1055/s-2006-954529 ◽

2006 ◽

Vol 31 (05) ◽

Author(s):

S Keipert ◽

J Wessels ◽

M Klingenspor ◽

J Rozman

Keyword(s):

Adipose Tissue ◽

Metabolic Rate ◽

Obese Mice

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COMBINATION OF POTASSIUM PERCHLORATE AND PROPYLTHIOURACIL IN THE TREATMENT OF THYROTOXICOSIS

Acta Endocrinologica ◽

10.1530/acta.0.0570565 ◽

1968 ◽

Vol 57 (4) ◽

pp. 565-577 ◽

Cited By ~ 4

Author(s):

K. E. Røkke ◽

J. H. Vogt

Keyword(s):

Drug Therapy ◽

Side Effects ◽

Metabolic Rate ◽

Total Cholesterol ◽

Basal Metabolic Rate ◽

Combined Therapy ◽

Combined Treatment ◽

Control Measures ◽

Potassium Perchlorate ◽

Plasma Total Cholesterol

ABSTRACT A report is given on 95 thyrotoxic patients treated with a combination of 400 mg propylthiouracil and 400 mg of potassium perchlorate. Perchlorate was stopped when a marked remission of symptoms was obtained, on an average after less than 7 weeks. Euthyroidism was found on an average after 7.2 weeks. The basal metabolic rate, PBI, plasma total cholesterol and weight showed a fairly rapid normalization. Thirteen of the 95 patients were given radio-iodine therapy shortly before drug therapy was started. The remaining 82 cases were grouped together with the 23 cases previously reported. Of the total of 105 cases, 96 became euthyroid on combined therapy. For the frequency of side-effects, the thirteen cases mentioned above were included, giving a total of 118 cases. Eight cases showed an increase in goitre size and 15 cases had other side-effects, of which three were granulocytopenia due to propylthiouracil. The possibility of a higher frequency of mainly minor side-effects on combined therapy has to be balanced against the seemingly rapid and reliable therapeutic effect. Combined treatment, perhaps with even smaller doses than reported here, can be recommended in selected cases of thyrotoxicosis where a shortening of the thyrotoxic state seems of importance, or possibly where difficulties due to iodine exposure may be anticipated, provided adequate control measures are taken.

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