Skeletal muscle thermogenesis enables aquatic life in the smallest marine mammal

Science ◽  
2021 ◽  
Vol 373 (6551) ◽  
pp. 223-225
Author(s):  
Traver Wright ◽  
Randall W. Davis ◽  
Heidi C. Pearson ◽  
Michael Murray ◽  
Melinda Sheffield-Moore
Keyword(s):  
Skeletal Muscle ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Tissue Level ◽  
Whole Body ◽  
Sea Otter ◽  
Aquatic Life ◽  
Respiratory Capacity ◽  
Metabolic Remodeling ◽  
Whole Body Metabolism

Basal metabolic rate generally scales with body mass in mammals, and variation from predicted levels indicates adaptive metabolic remodeling. As a thermogenic adaptation for living in cool water, sea otters have a basal metabolic rate approximately three times that of the predicted rate; however, the tissue-level source of this hypermetabolism is unknown. Because skeletal muscle is a major determinant of whole-body metabolism, we characterized respiratory capacity and thermogenic leak in sea otter muscle. Compared with that of previously sampled mammals, thermogenic muscle leak capacity was elevated and could account for sea otter hypermetabolism. Muscle respiratory capacity was modestly elevated and reached adult levels in neonates. Premature metabolic development and high leak rate indicate that sea otter muscle metabolism is regulated by thermogenic demand and is the source of basal hypermetabolism.

scholarly journals Skeletal muscle enhancer interactions identify genes controlling whole-body metabolism

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kristine Williams ◽  
Lars R. Ingerslev ◽  
Jette Bork-Jensen ◽  
Martin Wohlwend ◽  
Ann Normann Hansen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Whole Body ◽  
Whole Body Metabolism

Twenty-four-hour energy expenditure and basal metabolic rate measured in a whole-body indirect calorimeter in Gambian men

1990 ◽  
Vol 51 (4) ◽  
pp. 563-570 ◽  
Author(s):  
G Minghelli ◽  
Y Schutz ◽  
A Charbonnier ◽  
R Whitehead ◽  
E Jéquier
Keyword(s):  
Energy Expenditure ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Whole Body

Whole Body Protein Turnover in Chronically Undernourished Individuals

1994 ◽  
Vol 86 (4) ◽  
pp. 441-446 ◽  
Author(s):  
M. J. Soares ◽  
L. S. Piers ◽  
P. S. Shetty ◽  
A. A. Jackson ◽  
J. C. Waterlow
Keyword(s):  
Body Weight ◽  
Protein Synthesis ◽  
Metabolic Rate ◽  
Muscle Mass ◽  
Basal Metabolic Rate ◽  
Normal Weight ◽  
Fat Free Mass ◽  
Whole Body ◽  
Body Protein ◽  
Chronic Undernutrition

1. Two groups of adult men were studied in Bangalore, India, under identical conditions: the ‘normal weight’ subjects (mean body mass index 20.8 kg/m2) were medical students of the institute with access to habitual energy and protein intakes ad libitum. The other group, designated ‘undernourished’, were labourers on daily wages (mean body mass index 16.7 kg/m2). 2. In an earlier study we obtained lower absolute values for both basal metabolic rate and protein synthesis in the undernourished subjects; however, when the data were expressed on a body weight or fat-free mass basis, a trend towards higher rates of protein synthesis, as well as higher basal metabolic rate, was evident. The suggestion was made that such results reflected the relatively higher energy intakes per kg body weight of the undernourished subjects on the day of study. The objective of the present study was therefore to control for the dietary intake during the measurement of whole body protein turnover. 3. In the present study dietary intakes were equated on a body weight basis; however, expressed per kg fat-free mass, the normal weight subjects had received marginally higher intakes of energy and protein. The results, however, were similar to those of the previous study. In absolute terms, basal metabolic rate, protein synthesis and breakdown were lower in the undernourished subjects. When expressed per kg body weight or per kg fat-free mass, the undernourished subjects had higher basal metabolic rates than the well-nourished subjects, whereas no differences were seen in the rate of protein synthesis or breakdown. 4. Estimates of muscle mass, based on creatinine excretion, indicated that the undernourished subjects had a higher proportion of non-muscle to muscle mass. Nitrogen flux (Q) was determined from 15N abundance in two end products, urea (Qu) and ammonia (Qa). The ratio Qu/Qa was increased in the undernourished subjects and was significantly correlated with the ratio of non-muscle to muscle mass (r = 0.81; P < 0.005). These results fit in with our earlier suggestion of a greater proportion of non-muscle (visceral) mass in undernourished subjects. 5. The present data suggest that there are no changes in the rate of protein synthesis or breakdown in chronic undernutrition when results are expressed, conventionally, per kg fat-free mass. It can be theoretically shown, however, that there could be a 15% reduction in the rate of turnover of the visceral tissues in chronic undernutrition. This, together with the reduced urinary nitrogen excretion, would contribute to nitrogen economy in these individuals.

Activation of mTORC1 in skeletal muscle regulates whole-body metabolism through FGF21

2015 ◽  
Vol 8 (402) ◽  
pp. ra113-ra113 ◽  
Author(s):  
Maitea Guridi ◽  
Lionel A. Tintignac ◽  
Shuo Lin ◽  
Barbara Kupr ◽  
Perrine Castets ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Whole Body ◽  
Whole Body Metabolism

scholarly journals Nutritional influences on age-related skeletal muscle loss

2013 ◽  
Vol 73 (1) ◽  
pp. 16-33 ◽  
Author(s):  
Ailsa A. Welch
Keyword(s):  
Skeletal Muscle ◽  
Vitamin D ◽  
Fruits And Vegetables ◽  
Muscle Metabolism ◽  
Ubiquitin Proteasome System ◽  
Whole Body ◽  
Muscle Loss ◽  
Age Related ◽  
Anti Oxidant ◽  
Whole Body Metabolism

Age-related muscle loss impacts on whole-body metabolism and leads to frailty and sarcopenia, which are risk factors for fractures and mortality. Although nutrients are integral to muscle metabolism the relationship between nutrition and muscle loss has only been extensively investigated for protein and amino acids. The objective of the present paper is to describe other aspects of nutrition and their association with skeletal muscle mass. Mechanisms for muscle loss relate to imbalance in protein turnover with a number of anabolic pathways of which the mechanistic TOR pathway and the IGF-1–Akt–FoxO pathways are the most characterised. In terms of catabolism the ubiquitin proteasome system, apoptosis, autophagy, inflammation, oxidation and insulin resistance are among the major mechanisms proposed. The limited research associating vitamin D, alcohol, dietary acid–base load, dietary fat and anti-oxidant nutrients with age-related muscle loss is described. Vitamin D may be protective for muscle loss; a more alkalinogenic diet and diets higher in the anti-oxidant nutrients vitamin C and vitamin E may also prevent muscle loss. Although present recommendations for prevention of sarcopenia focus on protein, and to some extent on vitamin D, other aspects of the diet including fruits and vegetables should be considered. Clearly, more research into other aspects of nutrition and their role in prevention of muscle loss is required.

scholarly journals Branched-chain Amino Acids: Catabolism in Skeletal Muscle and Implications for Muscle and Whole-body Metabolism

2021 ◽  
Vol 12 ◽  
Author(s):  
Gagandeep Mann ◽  
Stephen Mora ◽  
Glory Madu ◽  
Olasunkanmi A. J. Adegoke
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Chronic Diseases ◽  
Branched Chain Amino Acids ◽  
Whole Body ◽  
Management Options ◽  
Impaired Metabolism ◽  
Whole Body Metabolism ◽  
Branched Chain ◽  
The Impact

Branched-chain amino acids (BCAAs) are critical for skeletal muscle and whole-body anabolism and energy homeostasis. They also serve as signaling molecules, for example, being able to activate mammalian/mechanistic target of rapamycin complex 1 (mTORC1). This has implication for macronutrient metabolism. However, elevated circulating levels of BCAAs and of their ketoacids as well as impaired catabolism of these amino acids (AAs) are implicated in the development of insulin resistance and its sequelae, including type 2 diabetes, cardiovascular disease, and of some cancers, although other studies indicate supplements of these AAs may help in the management of some chronic diseases. Here, we first reviewed the catabolism of these AAs especially in skeletal muscle as this tissue contributes the most to whole body disposal of the BCAA. We then reviewed emerging mechanisms of control of enzymes involved in regulating BCAA catabolism. Such mechanisms include regulation of their abundance by microRNA and by post translational modifications such as phosphorylation, acetylation, and ubiquitination. We also reviewed implications of impaired metabolism of BCAA for muscle and whole-body metabolism. We comment on outstanding questions in the regulation of catabolism of these AAs, including regulation of the abundance and post-transcriptional/post-translational modification of enzymes that regulate BCAA catabolism, as well the impact of circadian rhythm, age and mTORC1 on these enzymes. Answers to such questions may facilitate emergence of treatment/management options that can help patients suffering from chronic diseases linked to impaired metabolism of the BCAAs.

scholarly journals Association Between Cardiac High-Energy Phosphate Metabolism and Whole Body Metabolism in Healthy Female Adults

2021 ◽  
pp. 393-399
Author(s):  
P WIBOWO ◽  
S CHARMAN ◽  
N OKWOSE ◽  
L VELICKI ◽  
D POPOVIC ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
High Energy ◽  
Whole Body ◽  
Phosphate Metabolism ◽  
High Energy Phosphate ◽  
Glucose Levels ◽  
Whole Body Metabolism ◽  
High Energy Phosphate Metabolism ◽  
The Relationship

Decline in cardiac high-energy phosphate metabolism [phosphocreatine-to-ATP (PCr/ATP) ratio] and whole body metabolism increase the risk of heart failure and metabolic diseases. The aim of the present study was to assess the relationship between PCr/ATP ratio and measures of body metabolic function. A total of 35 healthy women (56±14.0 years of age) underwent cardiac 31P magnetic resonance spectroscopy to assess PCr/ATP ratio – an index of cardiac high-energy phosphate metabolism. Fasting and 2-hour glucose levels were assessed using oral glucose tolerance test. Indirect calorimetry was performed to determine oxygen consumption and resting metabolic rate. There were no significant relationships between PCr/ATP ratio and resting metabolic rate (r=-0.09, p=0.62), oxygen consumption (r=-0.11, p=0.54), fasting glucose levels (r=-0.31, p=0.07), and 2-hour plasma glucose (r=-0.10, p=0.58). Adjusted analysis for covariates including age, body mass index, fat mass, and physical activity, had no significant influence on the relationship between PCr/ATP ratio and body metabolism. In conclusion, the lack of relationship between cardiac PCr/ATP ratio, glucose control and metabolic rate may suggest that overall metabolic function does not influence cardiac high-energy phosphate metabolism.

scholarly journals Are basal metabolic rate prediction equations appropriate for female children and adolescents?

1996 ◽  
Vol 81 (6) ◽  
pp. 2407-2414 ◽  
Author(s):  
William W. Wong ◽  
Nancy F. Butte ◽  
Albert C. Hergenroeder ◽  
Rebecca B. Hill ◽  
Janice E. Stuff ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Children And Adolescents ◽  
Basal Metabolic Rate ◽  
Whole Body ◽  
Accurate Estimation ◽  
Prediction Equations ◽  
Rate Prediction ◽  
Day Range ◽  
Energy Needs ◽  
Female Children

Wong, William W., Nancy F. Butte, Albert C. Hergenroeder, Rebecca B. Hill, Janice E. Stuff, and E. O’Brian Smith. Are basal metabolic rate prediction equations appropriate for female children and adolescents? J. Appl. Physiol. 81(6): 2407–2414, 1996.—The basal metabolic rate (BMR), which accounts for 50–70% of total energy expenditure, is essential for estimation of patient and population energy needs. Numerous equations have been formulated for prediction of human BMR. Most equations in current use are based on measurements of Caucasians performed more than four decades ago. We evaluated 10 prediction equations commonly used for estimation of BMR in 76 Caucasian and 42 African-American girls between 8 and 17 yr of age against BMR measured by whole-body calorimetry. The majority of the prediction equations (9 of 10) overestimated BMR by 60 ± 46 kcal/day (range, 15–176 kcal/day). This overestimation was found to be significantly greater ( P < 0.05) for African-Americans (77 ± 17 kcal/day) than for Caucasians (25 ± 17 kcal/day) in six equations, controlling for age, weight, and sexual maturity. We conclude that ethnicity is an important factor in estimation of the BMR and that the current prediction equations are not appropriate for accurate estimation of the BMR of individual female children and adolescents.

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