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Gębczyński AK, Sadowska J, Konarzewski M. Differences in the range of thermoneutral zone between mouse strains: potential effects on translational research. Am J Physiol Regul Integr Comp Physiol 2024; 326:R91-R99. [PMID: 38009211 DOI: 10.1152/ajpregu.00154.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/27/2023] [Accepted: 11/20/2023] [Indexed: 11/28/2023]
Abstract
Laboratory mice are commonly used for studies emulating human metabolism. To render human energetics, their ratio of daily (DEE) to basal (BMR) energy expenditure of 1.7-1.8 should be maintained. However, the DEE/BMR ratio strongly depends on whether a given study using a mouse model is carried out above, or below the lower critical temperature (LCT) of the thermoneutral zone, which is rarely considered in translational research. Here, we used mice artificially selected for high or low rates of BMR along with literature data to analyze the effect of ambient temperature on possible systematic bias in DEE/BMR. We demonstrated that the estimated LCTs of mice from the high and low BMR lines differ by more than 7°C. Furthermore, the range of variation of LCTs of mouse strains used in translational research spans from 23 to 33°C. Differences between LCTs in our selected mice and other mouse strains are mirrored by differences in their DEE-to-BMR ratio, on average increasing it at the rate of 0.172°C-1 at temperatures below LCT. Given the wide range of LCTs in different mouse strains, we conclude that the energetic cost of thermoregulation may differ greatly for different mouse strains with a potentially large impact on translational outcomes. Thus, the LCT of a given mouse strain is an important factor that must be considered in designing translational studies.
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Affiliation(s)
| | - Julita Sadowska
- Faculty of Biology, University of Białystok, Białystok, Poland
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2
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Hebart ML, Herd RM, Oddy VH, Geiser F, Pitchford WS. Selection for lower residual feed intake in mice is accompanied by increased body fatness and lower activity but not lower metabolic rate. ANIMAL PRODUCTION SCIENCE 2021. [DOI: 10.1071/an20664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Mice bred to be genetically different in feed efficiency were used in this experiment designed to help improve our knowledge of the biological basis of variation in feed efficiency between individual animals.
Aims
This experiment used mice to explore the metabolic basis of genetic variation in feed efficiency in the growing animal.
Methods
Mice bred to differ in residual feed intake (RFI) recorded over a postweaning test were used. After 11 generations of divergent selection, mice in groups were tested for RFI from 6 to 8, 8 to 10, and 10 to 12 weeks of age, and measured for traits describing the ability to digest feed, body composition, protein turnover, basal and resting metabolic rate, and level of activity.
Key results
Compared with the low-RFI (high efficiency) line mice, high-RFI mice consumed 28% more feed per day over their RFI-test, were no heavier, were leaner (16% less total fat per unit of bodyweight), did not differ in the fractional synthesis rate of protein in skeletal muscle or in liver, and had similar basal metabolic rates at 33°C. On an energy basis, the selection lines did not differ in energy retained in body tissue gain, which represented only 1.8% of metabolisable energy intake. The remaining 98.2% was lost as heat. Of the processes measured contributing to the higher feed intake by the high-RFI mice, 47% of the extra feed consumed was lost in faeces and urine, activity was 84% higher and accounted for 24%, the cost of protein gain was 6% higher and accounted for 2%, and the energy cost of digesting and absorbing the extra feed consumed and basal heat production could have accounted for 11 and 15% each.
Conclusions
Selection for low RFI (high efficiency) in mice was accompanied by an increase in body fat, an improvement in the process of digestion, a lower rate of protein turnover and a much lower level of activity. Selection did not result in major change in basal metabolic rate.
Implications
This experiment with mice provided new information on the biological basis of genetic differences in feed efficiency. The experiment investigated the relative importance of major energy-consuming metabolic processes and was able to quantify the responses in protein turnover and level of activity, being responses in energy-consuming processes that have proven difficult to quantitatively demonstrate in large farm animals.
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Blais A, Chaumontet C, Azzout-Marniche D, Piedcoq J, Fromentin G, Gaudichon C, Tomé D, Even PC. Low-protein diet-induced hyperphagia and adiposity are modulated through interactions involving thermoregulation, motor activity, and protein quality in mice. Am J Physiol Endocrinol Metab 2018; 314:E139-E151. [PMID: 29138228 DOI: 10.1152/ajpendo.00318.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Low protein (LP)-containing diets can induce overeating in rodents and possibly in humans in an effort to meet protein requirement, but the effects on energy expenditure (EE) are unclear. The present study evaluated the changes induced by reducing dietary protein from 20% to 6%-using either soy protein or casein-on energy intake, body composition, and EE in mice housed at 22°C or at 30°C (thermal neutrality). LP feeding increased energy intake and adiposity, more in soy-fed than in casein-fed mice, but also increased EE, thus limiting fat accumulation. The increase in EE was due mainly to an increase in spontaneous motor activity related to EE and not to thermoregulation. However, the high cost of thermoregulation at 22°C and the subsequent heat exchanges between nonshivering thermogenesis, motor activity, and feeding induced large differences in adaptation between mice housed at 22°C and at 30°C.
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Affiliation(s)
- Anne Blais
- UMR Physiologie de la Nutrition et du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay , Paris , France
| | - Catherine Chaumontet
- UMR Physiologie de la Nutrition et du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay , Paris , France
| | - Dalila Azzout-Marniche
- UMR Physiologie de la Nutrition et du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay , Paris , France
| | - Julien Piedcoq
- UMR Physiologie de la Nutrition et du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay , Paris , France
| | - Gilles Fromentin
- UMR Physiologie de la Nutrition et du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay , Paris , France
| | - Claire Gaudichon
- UMR Physiologie de la Nutrition et du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay , Paris , France
| | - Daniel Tomé
- UMR Physiologie de la Nutrition et du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay , Paris , France
| | - Patrick C Even
- UMR Physiologie de la Nutrition et du Comportement Alimentaire, AgroParisTech, Institut National de la Recherche Agronomique, Université Paris Saclay , Paris , France
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4
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Black or white? Physiological implications of roost colour and choice in a microbat. J Therm Biol 2016; 60:162-70. [PMID: 27503729 DOI: 10.1016/j.jtherbio.2016.07.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/15/2016] [Indexed: 12/16/2022]
Abstract
Although roost choice in bats has been studied previously, little is known about how opposing roost colours affect the expression of torpor quantitatively. We quantified roost selection and thermoregulation in a captive Australian insectivorous bat, Nyctophilus gouldi (n=12) in winter when roosting in black and white coloured boxes using temperature-telemetry. We quantified how roost choice influences torpor expression when food was provided ad libitum or restricted in bats housed together in an outdoor aviary exposed to natural fluctuations of ambient temperature. Black box temperatures averaged 5.1°C (maximum 7.5°C) warmer than white boxes at their maximum daytime temperature. Bats fed ad libitum chose black boxes on most nights (92.9%) and on 100% of nights when food-restricted. All bats used torpor on all study days. However, bats fed ad libitum and roosting in black boxes used shorter torpor and spent more time normothermic/active at night than food-restricted bats and bats roosting in white boxes. Bats roosting in black boxes also rewarmed passively more often and to a higher skin temperature than those in white boxes. Our study suggests that N. gouldi fed ad libitum select warmer roosts in order to passively rewarm to a higher skin temperature and thus save energy required for active midday rewarming as well as to maintain a normothermic body temperature for longer periods at night. This study shows that colour should be considered when deploying bat boxes; black boxes are preferable for those bats that use passive rewarming, even in winter when food availability is reduced.
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Piper MDW, Selman C, Speakman JR, Partridge L. Using doubly-labeled water to measure energy expenditure in an important small ectotherm Drosophila melanogaster. J Genet Genomics 2014; 41:505-12. [PMID: 25269676 PMCID: PMC4507022 DOI: 10.1016/j.jgg.2014.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/29/2014] [Accepted: 07/29/2014] [Indexed: 01/24/2023]
Abstract
Energy expenditure is a key variable in the study of ageing, and the fruit fly Drosophila melanogaster is a model organism that has been used to make step changes in our understanding of the ageing process. Standard methods for measurement of energy expenditure involve placing individuals in metabolic chambers where their oxygen consumption and CO2 production can be quantified. These measurements require separating individuals from any social context, and may only poorly reflect the environment in which the animals normally live. The doubly-labeled water (DLW) method is an isotope-based technique for measuring energy expenditure which overcomes these problems. However, technical challenges mean that the smallest animals this method has been previously applied to weighed 50–200 mg. We overcame these technical challenges to measure energy demands in Drosophila weighing 0.78 mg. Mass-specific energy expenditure varied between 43 and 65 mW·g−1. These estimates are considerably higher than estimates using indirect calorimetry of Drosophila in small metabolic chambers (around 18 mW·g−1). The methodology we have established extends downwards by three orders of magnitude the size of animals that can be measured using DLW. This approach may be of considerable value in future ageing research attempting to understand the genetic and genomic basis of ageing.
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Affiliation(s)
- Matthew D W Piper
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK
| | - Colin Selman
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK; Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK; Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
| | - John R Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK; State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Linda Partridge
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK
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Lipidomics Reveals Mitochondrial Membrane Remodeling Associated with Acute Thermoregulation in a Rodent with a Wide Thermoneutral Zone. Lipids 2014; 49:715-30. [DOI: 10.1007/s11745-014-3900-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/20/2014] [Indexed: 12/13/2022]
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7
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Speakman JR, Al-Jothery AH, Król E, Hawkins J, Chetoui A, Saint-Lambert A, Gamo Y, Shaw SC, Valencak T, Bünger L, Hill W, Vaanholt L, Hambly C. Limits to sustained energy intake. XXII. Reproductive performance of two selected mouse lines with different thermal conductance. J Exp Biol 2014; 217:3718-32. [DOI: 10.1242/jeb.103705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Abstract
Maximal sustained energy intake (SusEI) appears limited, but the factors imposing the limit are disputed. We studied reproductive performance in two lines of mice selected for high and low food intake (MH and ML, respectively), and known to have large differences in thermal conductance (29% higher in the MH line at 21°C). When these mice raised their natural litters, their metabolisable energy intake significantly increased over the first 13 days of lactation and then reached a plateau. At peak lactation, MH mice assimilated on average 45.3 % more energy than ML mice (222.9±7.1 and 153.4±12.5 kJ day-1, N=49 and 24, respectively). Moreover, MH mice exported on average 62.3 kJ day-1 more energy as milk than ML mice (118.9±5.3 and 56.6±5.4 kJ day-1, N= subset of 32 and 21, respectively). The elevated milk production of MH mice enabled them to wean litters (65.2±2.1 g) that were on average 50.2% heavier than litters produced by ML mothers (43.4±3.0 g), and pups that were on average 27.2% heavier (9.9±0.2 and 7.8±0.2 g, respectively). Lactating mice in both lines had significantly longer and heavier guts compared to non-reproductive mice. However, inconsistent with the central limit hypothesis, the ML mice had significantly longer and heavier intestines than MH mice. An experiment where the mice raised litters of the opposing line demonstrated that lactation performance was not limited by offspring growth capacity. Our findings are consistent with the idea that the SusEI at peak lactation is constrained by the capacity of the mothers to dissipate body heat.
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Affiliation(s)
| | | | | | | | | | | | - Yuko Gamo
- University of Aberdeen, United Kingdom
| | | | | | - Lutz Bünger
- Scotland's Rural College (SRUC), United Kingdom
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8
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Even PC. Body size, spontaneous activity and thermogenesis effects on energy expenditure: an introduction to a topic on energy metabolism. Front Physiol 2013; 4:301. [PMID: 24146654 PMCID: PMC3797956 DOI: 10.3389/fphys.2013.00301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 10/01/2013] [Indexed: 12/11/2022] Open
Affiliation(s)
- Patrick C Even
- UMR914 Nutrition Physiology and Ingestive Behavior, AgroParisTech INRA, Paris, France
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9
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10
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Speakman JR, Keijer J. Not so hot: Optimal housing temperatures for mice to mimic the thermal environment of humans. Mol Metab 2012; 2:5-9. [PMID: 24024125 DOI: 10.1016/j.molmet.2012.10.002] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 10/10/2012] [Accepted: 10/16/2012] [Indexed: 11/30/2022] Open
Abstract
It has been argued that mice should be housed at 30 °C to best mimic the thermal conditions experienced by humans, and that the current practice of housing mice at 20-22 °C impairs the suitability of mice as a model for human physiology and disease. In the current paper we challenge this notion. First, we show that humans routinely occupy environments about 3 °C below their lower critical temperature (T lc), which when lightly clothed is about 23 °C. Second, we review the data for the T lc of mice. Mouse T lc is dependent on body weight and about 26-28 °C for adult mice weighing >25 g. The equivalent temperature to that normally experienced by humans for most single housed adult mice is therefore 23-25 °C. Group housing or providing the mice with bedding and nesting material might lower this to about 20-22 °C, close to current standard practice.
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Affiliation(s)
- John R Speakman
- Key State Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang, Beijing 100101, People's Republic of China ; Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, Scotland, UK
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11
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Careau V, Garland T. Performance, personality, and energetics: correlation, causation, and mechanism. Physiol Biochem Zool 2012; 85:543-71. [PMID: 23099454 DOI: 10.1086/666970] [Citation(s) in RCA: 307] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The study of phenotypic evolution should be an integrative endeavor that combines different approaches and crosses disciplinary and phylogenetic boundaries to consider complex traits and organisms that historically have been studied in isolation from each other. Analyses of individual variation within populations can act to bridge studies focused at the levels of morphology, physiology, biochemistry, organismal performance, behavior, and life history. For example, the study of individual variation recently facilitated the integration of behavior into the concept of a pace-of-life syndrome and effectively linked the field of energetics with research on animal personality. Here, we illustrate how studies on the pace-of-life syndrome and the energetics of personality can be integrated within a physiology-performance-behavior-fitness paradigm that includes consideration of ecological context. We first introduce key concepts and definitions and then review the rapidly expanding literature on the links between energy metabolism and personality traits commonly studied in nonhuman animals (activity, exploration, boldness, aggressiveness, sociability). We highlight some empirical literature involving mammals and squamates that demonstrates how emerging fields can develop in rather disparate ways because of historical accidents and/or particularities of different kinds of organisms. We then briefly discuss potentially interesting avenues for future conceptual and empirical research in relation to motivation, intraindividual variation, and mechanisms underlying trait correlations. The integration of performance traits within the pace-of-life-syndrome concept has the potential to fill a logical gap between the context dependency of selection and how energetics and personality are expected to interrelate. Studies of how performance abilities and/or aspects of Darwinian fitness relate to both metabolic rate and personality traits are particularly lacking.
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Affiliation(s)
- Vincent Careau
- Department of Biology, University of California, Riverside, California 92521, USA.
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12
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Konarzewski M, Książek A. Determinants of intra-specific variation in basal metabolic rate. J Comp Physiol B 2012; 183:27-41. [PMID: 22847501 PMCID: PMC3536993 DOI: 10.1007/s00360-012-0698-z] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 06/10/2012] [Accepted: 07/13/2012] [Indexed: 12/02/2022]
Abstract
Basal metabolic rate (BMR) provides a widely accepted benchmark of metabolic expenditure for endotherms under laboratory and natural conditions. While most studies examining BMR have concentrated on inter-specific variation, relatively less attention has been paid to the determinants of within-species variation. Even fewer studies have analysed the determinants of within-species BMR variation corrected for the strong influence of body mass by appropriate means (e.g. ANCOVA). Here, we review recent advancements in studies on the quantitative genetics of BMR and organ mass variation, along with their molecular genetics. Next, we decompose BMR variation at the organ, tissue and molecular level. We conclude that within-species variation in BMR and its components have a clear genetic signature, and are functionally linked to key metabolic process at all levels of biological organization. We highlight the need to integrate molecular genetics with conventional metabolic field studies to reveal the adaptive significance of metabolic variation. Since comparing gene expressions inter-specifically is problematic, within-species studies are more likely to inform us about the genetic underpinnings of BMR. We also urge for better integration of animal and medical research on BMR; the latter is quickly advancing thanks to the application of imaging technologies and ‘omics’ studies. We also suggest that much insight on the biochemical and molecular underpinnings of BMR variation can be gained from integrating studies on the mammalian target of rapamycin (mTOR), which appears to be the major regulatory pathway influencing the key molecular components of BMR.
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13
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Even PC, Nadkarni NA. Indirect calorimetry in laboratory mice and rats: principles, practical considerations, interpretation and perspectives. Am J Physiol Regul Integr Comp Physiol 2012; 303:R459-76. [PMID: 22718809 DOI: 10.1152/ajpregu.00137.2012] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In this article, we review some fundamentals of indirect calorimetry in mice and rats, and open the discussion on several debated aspects of the configuration and tuning of indirect calorimeters. On the particularly contested issue of adjustment of energy expenditure values for body size and body composition, we discuss several of the most used methods and their results when tested on a previously published set of data. We conclude that neither body weight (BW), exponents of BW, nor lean body mass (LBM) are sufficient. The best method involves fitting both LBM and fat mass (FM) as independent variables; for low sample sizes, the model LBM + 0.2 FM can be very effective. We also question the common calorimetry design that consists of measuring respiratory exchanges under free-feeding conditions in several cages simultaneously. This imposes large intervals between measures, and generally limits data analysis to mean 24 h or day-night values of energy expenditure. These are then generally compared with energy intake. However, we consider that, among other limitations, the measurements of Vo(2), Vco(2), and food intake are not precise enough to allow calculation of energy balance in the small 2-5% range that can induce significant long-term alterations of energy balance. In contrast, we suggest that it is necessary to work under conditions in which temperature is set at thermoneutrality, food intake totally controlled, activity precisely measured, and data acquisition performed at very high frequency to give access to the part of the respiratory exchanges that are due to activity. In these conditions, it is possible to quantify basal energy expenditure, energy expenditure associated with muscular work, and response to feeding or to any other metabolic challenge. This reveals defects in the control of energy metabolism that cannot be observed from measurements of total energy expenditure in free feeding individuals.
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Affiliation(s)
- Patrick C Even
- UMR Institut National de la Recherche Agronomique/AgroParisTech 914, 16 Rue Claude Bernard, Laboratory of Nutrition Physiology and Feeding Behavior, 75005, Paris, France.
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14
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Kaseloo P, Crowell M, Jones J, Heideman P. Variation in basal metabolic rate and activity in relation to reproductive condition and photoperiod in white-footed mice (Peromyscus leucopus). CAN J ZOOL 2012. [DOI: 10.1139/z2012-026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A naturally variable life-history trait with underlying physiological variation is the photoperiodic response of many temperate-zone rodents, including white-footed mice (Peromyscus leucopus (Rafinesque, 1818)). Male P. leucopus were obtained from a short photoperiod responsive (R) line, artificially selected for reproductive suppression in short-day conditions (SD) and a nonresponsive (NR) line selected for reproductive maturity in SD. We tested for variation in metabolic rate between lines in SD and long-day conditions (LD). NR mice consumed 34% more food than R mice, without concomitant increase in body mass in SD. Basal metabolic rate (BMR) was found to be significantly greater in NR than R mice, and NR mice were found to engage in significantly more spontaneous (daily) locomotor activity. Energy-use estimates based on 24 h respirometry matched closely the level of intake reported for individual mice. The increased BMR and average daily metabolic rate in NR mice was correlated with testis size, but not with major central organs or digestibility. No significant difference in BMR or activity was found in mice from the same lines held in LD. Elevated intake in SD mice appears to be associated with differences in fertility and not other aspects of physiology in the respective lines.
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Affiliation(s)
- P.A. Kaseloo
- Department of Biology, Virginia State University, P.O. Box 9064, Virginia State University, VA 23806, USA
| | - M.G. Crowell
- Department of Biology, Virginia State University, P.O. Box 9064, Virginia State University, VA 23806, USA
| | - J.J. Jones
- Department of Biology, Virginia State University, P.O. Box 9064, Virginia State University, VA 23806, USA
| | - P.D. Heideman
- Department of Biology, College of William and Mary, Williamsburg, VA 23187, USA
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Meyer CW, Willershäuser M, Jastroch M, Rourke BC, Fromme T, Oelkrug R, Heldmaier G, Klingenspor M. Adaptive thermogenesis and thermal conductance in wild-type and UCP1-KO mice. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1396-406. [PMID: 20826705 DOI: 10.1152/ajpregu.00021.2009] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We compared maximal cold-induced heat production (HPmax) and cold limits between warm (WA; 27°C), moderate cold (MCA; 18°C), or cold acclimated (CA; 5°C) wild-type and uncoupling-protein 1 knockout (UCP1-KO) mice. In wild-type mice, HPmax was successively increased after MCA and CA, and the cold limit was lowered to -8.3°C and -18.0°C, respectively. UCP1-KO mice also increased HPmax in response to MCA and CA, although to a lesser extent. Direct comparison revealed a maximal cold-induced recruitment of heat production by +473 mW and +227 mW in wild-type and UCP1-KO mice, respectively. The increase in cold tolerance of UCP1-KO mice from -0.9°C in MCA to -10.1°C in CA could not be directly related to changes in HPmax, indicating that UCP1-KO mice used the dissipated heat more efficiently than wild-type mice. As judged from respiratory quotients, acutely cold-challenged UCP1-KO mice showed a delayed transition toward lipid oxidation, and 5-h cold exposure revealed diminished physical activity and less variability in the control of metabolic rate. We conclude that BAT is required for maximal adaptive thermogenesis but also allows metabolic flexibility and a rapid switch toward sustained lipid-fuelled thermogenesis as an acute response to cold. In both CA groups, expression of contractile proteins (myosin heavy-chain isoforms) showed minor training effects in skeletal muscles, while cardiac muscle of UCP1-KO mice had novel expression of beta cardiac isoform. Neither respiration nor basal proton conductance of skeletal muscle mitochondria were different between genotypes. In subcutaneous white adipose tissue of UCP1-KO mice, cold exposure increased cytochrome-c oxidase activity and expression of the cell death-inducing DFFA-like effector A by 3.6-fold and 15-fold, respectively, indicating the recruitment of mitochondria-rich brown adipocyte-like cells. Absence of functional BAT leads to remodeling of white adipose tissue, which may significantly contribute to adaptive thermogenesis during cold acclimation.
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Affiliation(s)
- Carola W Meyer
- Dept. of Animal Physiology, Faculty of Biology, Philipps-Universität, Karl-von-Frisch Strasse 8, 35032 Marburg, Germany.
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16
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Banks R, Speakman JR, Selman C. Vitamin E supplementation and mammalian lifespan. Mol Nutr Food Res 2010; 54:719-25. [DOI: 10.1002/mnfr.200900382] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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17
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Hempenstall S, Picchio L, Mitchell SE, Speakman JR, Selman C. The impact of acute caloric restriction on the metabolic phenotype in male C57BL/6 and DBA/2 mice. Mech Ageing Dev 2010; 131:111-8. [PMID: 20064544 DOI: 10.1016/j.mad.2009.12.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Revised: 12/18/2009] [Accepted: 12/24/2009] [Indexed: 11/29/2022]
Abstract
Caloric restriction (CR) extends healthy lifespan in many organisms. DBA/2 mice, unlike C57BL/6 mice, are reported to be unresponsive to CR. To investigate potential differences underlying the CR response in male DBA/2 and C57BL/6 mice, we examined several metabolic parameters following acute (1-5 weeks) 30% CR. Acute CR decreased body mass (BM) in both strains, with lean and fat mass decreasing in proportion to BM. Resting metabolic rate (RMR) was unaltered by CR, following appropriate corrections for BM differences, although RMR was higher in DBA/2 compared to C57BL/6 mice. Acute CR decreased fed blood glucose levels in both strains, decreased fasting blood glucose in C57BL/6 mice but increased fasting levels in DBA/2 mice. Glucose tolerance improved after 1 week of CR in C57BL/6 mice but improved only after 4 weeks in DBA/2 mice. Acute CR had no effect on insulin levels, but lowered insulin sensitivity and decreased insulin-like growth factor-1 (IGF-1) levels in both strains. DBA/2 mice were hyperinsulinaemic and insulin resistant compared to C57BL/6 mice. These strain-specific differences in glucose homeostatic parameters may underlie the reported unresponsiveness of DBA/2 mice to CR. We also demonstrate delineation in the response of insulin and IGF-1 to acute CR in mice.
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Affiliation(s)
- Sarah Hempenstall
- Integrative Physiology, Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK
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18
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Rance KA, Hambly C, Dalgleish G, Fustin JM, Bünger L, Speakman JR. Quantitative trait Loci for regional adiposity in mouse lines divergently selected for food intake. Obesity (Silver Spring) 2007; 15:2994-3004. [PMID: 18198308 DOI: 10.1038/oby.2007.357] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
OBJECTIVE Obesity is thought to result from an interaction between genotype and environment. Excessive adiposity is associated with a number of important comorbidities; however, the risk of obesity-related disease varies with the distribution of fat throughout the body. The aim of this study was to map quantitative trait loci (QTLs) associated with regional fat depots in mouse lines divergently selected for food intake corrected for body mass. RESEARCH METHODS AND PROCEDURES Using an F2 intercross design (n = 457), the dry mass of regional white (subcutaneous, gonadal, retroperitoneal, and mesenteric) adipose tissue (WAT) and brown adipose tissue (BAT) depots were analyzed to map QTLs. RESULTS The total variance explained by the mapped QTL varied between 12% and 39% for BAT and gonadal fat depots, respectively. Using the genome-wide significance threshold, nine QTLs were associated with multiple fat depots. Chromosomes 4 and 19 were associated with WAT and BAT and chromosome 9 with WAT depots. Significant sex x QTL interactions were identified for gonadal fat on chromosomes 9, 16, and 19. The pattern of QTLs identified for the regional deposits showed the most similarity between retroperitoneal and gonadal fat, whereas BAT showed the least similarity to the WAT depots. Analysis of total fat mass explained in excess of 40% of total variance. DISCUSSION There was limited concordance between the QTLs mapped in our study and those reported previously. This is likely to reflect the unique nature of the mouse lines used. Results provide an insight into the genetic basis of regional fat distribution.
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Affiliation(s)
- Kellie A Rance
- Aberdeen Centre for Energy Regulation and Obesity, School of Biological Sciences, University of Aberdeen, UK.
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19
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Claret M, Smith MA, Batterham RL, Selman C, Choudhury AI, Fryer LG, Clements M, Al-Qassab H, Heffron H, Xu AW, Speakman JR, Barsh GS, Viollet B, Vaulont S, Ashford ML, Carling D, Withers DJ. AMPK is essential for energy homeostasis regulation and glucose sensing by POMC and AgRP neurons. J Clin Invest 2007; 117:2325-36. [PMID: 17671657 PMCID: PMC1934578 DOI: 10.1172/jci31516] [Citation(s) in RCA: 385] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 04/24/2007] [Indexed: 01/13/2023] Open
Abstract
Hypothalamic AMP-activated protein kinase (AMPK) has been suggested to act as a key sensing mechanism, responding to hormones and nutrients in the regulation of energy homeostasis. However, the precise neuronal populations and cellular mechanisms involved are unclear. The effects of long-term manipulation of hypothalamic AMPK on energy balance are also unknown. To directly address such issues, we generated POMC alpha 2KO and AgRP alpha 2KO mice lacking AMPK alpha2 in proopiomelanocortin- (POMC-) and agouti-related protein-expressing (AgRP-expressing) neurons, key regulators of energy homeostasis. POMC alpha 2KO mice developed obesity due to reduced energy expenditure and dysregulated food intake but remained sensitive to leptin. In contrast, AgRP alpha 2KO mice developed an age-dependent lean phenotype with increased sensitivity to a melanocortin agonist. Electrophysiological studies in AMPK alpha2-deficient POMC or AgRP neurons revealed normal leptin or insulin action but absent responses to alterations in extracellular glucose levels, showing that glucose-sensing signaling mechanisms in these neurons are distinct from those pathways utilized by leptin or insulin. Taken together with the divergent phenotypes of POMC alpha 2KO and AgRP alpha 2KO mice, our findings suggest that while AMPK plays a key role in hypothalamic function, it does not act as a general sensor and integrator of energy homeostasis in the mediobasal hypothalamus.
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Affiliation(s)
- Marc Claret
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Mark A. Smith
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Rachel L. Batterham
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Colin Selman
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Agharul I. Choudhury
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Lee G.D. Fryer
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Melanie Clements
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Hind Al-Qassab
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Helen Heffron
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Allison W. Xu
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - John R. Speakman
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Gregory S. Barsh
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Benoit Viollet
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Sophie Vaulont
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Michael L.J. Ashford
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - David Carling
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
| | - Dominic J. Withers
- Centre for Diabetes and Endocrinology, Rayne Institute, University College London, London, United Kingdom.
Neurosciences Institute, Pathology and Neuroscience Division, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom.
Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom.
Department of Genetics and Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA.
Aberdeen Centre for Energy Regulation and Obesity, University of Aberdeen, Aberdeen, United Kingdom.
INSERM U567, CNRS, UMR 8104, Institut Cochin, Université René Descartes, Paris, France
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20
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Rønning B, Jensen H, Moe B, Bech C. Basal metabolic rate: heritability and genetic correlations with morphological traits in the zebra finch. J Evol Biol 2007; 20:1815-22. [PMID: 17714299 DOI: 10.1111/j.1420-9101.2007.01384.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Studies of genetic variation in metabolic traits have so far not focused on birds. In our study population of captive zebra finches we found evidence for a significant heritable genetic component in basal metabolic rate (BMR). Heritability of all morphological traits investigated (body mass, head length, tars length and wing length) was significantly larger than zero. All traits were positively phenotypically correlated. Eight of 10 genetic correlations presented in this study differed significantly from zero, all being positive, suggesting the possibility of correlated responses to any selection acting on the traits. When conditioned on the genetic variance in body mass, the heritability of BMR was reduced from 25% to 4%. Hence, our results indicate that genetic changes in BMR through directional selection are possible, but the potential for adaptation independent of body mass may be limited.
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Affiliation(s)
- B Rønning
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
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21
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Speakman JR, Hambly C. Starving for life: what animal studies can and cannot tell us about the use of caloric restriction to prolong human lifespan. J Nutr 2007; 137:1078-86. [PMID: 17374682 DOI: 10.1093/jn/137.4.1078] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Caloric restriction (CR) is the only experimental nongenetic paradigm known to increase lifespan. It has broad applicability and extends the life of most species through a retardation of aging. There is considerable interest in the use of CR in humans, and animal studies can potentially tell us about the impacts. In this article we highlight some of the things that animal studies can tell us about CR in humans. Rodent studies indicate that the benefits of CR on lifespan extension are related to the extent of restriction. The benefits of CR, however, decline as the age of onset of treatment is delayed. Modeling these impacts suggests that if a 48-y-old man engaged in 30% CR until his normal life expectancy of 78, he might increase his life expectancy by 2.8 y. Exercise and cold exposure induce similar energy deficits, but animals respond to these energy deficits in different ways that have a minor impact on lifespan. Measurements of animal responses when they cease restriction indicate that prolonged CR does not diminish hunger, even though the animals may have been in long-term energy balance. Neuroendocrine profiles support the idea that animals under CR are continuously hungry. The feasibility of restricting intake in humans for many decades without long-term support is questionable. However, what is unclear from animal studies is whether taking drugs that suppress appetite will generate the same impact on longevity or whether the neuroendocrine correlates of hunger play an integral role in mediating CRs effects.
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Affiliation(s)
- John R Speakman
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, Scotland, UK.
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22
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McDonald JM, Nielsen MK. Renewed selection for heat loss in mice: Direct responses and correlated responses in feed intake, body weight, litter size, and conception rate1. J Anim Sci 2007; 85:658-66. [PMID: 17060417 DOI: 10.2527/jas.2006-465] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Divergent selection in mice was renewed in 3 independent replicates for high (MH) and low (ML) heat loss. An unselected control (MC) was maintained in all replicates. Heat loss was measured for individual male mice for 15 h, overnight in direct calorimeters. After 16 initial generations of selection followed by 26 generations of relaxed selection, divergent selection resumed for 9 generations. The realized selection applied was very close to the maximum possible selection according to the criteria and protocol. Selection differentials were greater for high than for low selection due to greater variation in the MH line. When corrected for SD, standardized selection differentials were similar for MH and ML selection. Unintended selection in MC was negligible. Realized heritability for divergence was 0.14 +/- 0.01, which was considerably less than that realized during the initial generations of selection (0.28 +/- 0.03). Realized heritabilities for MH selection (0.16 +/- 0.05) and for ML selection (0.07 +/- 0.06) were less, especially for ML selection, than were observed in the earlier generations. The difference in heat loss between MH and ML males was 55.7% of the MC mean at generation 51, compared with a difference of 53.6% in generation 15; this difference had decreased to 34.4% at the end of the relaxed selection (generation 42). For feed intake between 8 and 11 wk, MH and ML males differed by 34.0% of the MC mean by the end of the selection process. Body weight at 12 wk for MH and ML males was less than for MC males. Litter size response was positively related to the heat loss response. Conception rate was poorer in MH matings than in MC and ML matings.
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Affiliation(s)
- J M McDonald
- Department of Animal Science, University of Nebraska, Lincoln, NE 68583-0908, USA
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23
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Selman C, McLaren JS, Meyer C, Duncan JS, Redman P, Collins AR, Duthie GG, Speakman JR. Life-long vitamin C supplementation in combination with cold exposure does not affect oxidative damage or lifespan in mice, but decreases expression of antioxidant protection genes. Mech Ageing Dev 2006; 127:897-904. [PMID: 17092545 DOI: 10.1016/j.mad.2006.09.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 09/19/2006] [Accepted: 09/25/2006] [Indexed: 02/05/2023]
Abstract
Oxidative stress is suggested to be central to the ageing process, with endogenous antioxidant defence and repair mechanisms in place to minimize damage. Theoretically, supplementation with exogenous antioxidants might support the endogenous antioxidant system, thereby reducing oxidative damage, ageing-related functional decline and prolonging life- and health-span. Yet supplementation trials with antioxidants in animal models have had minimal success. Human epidemiological data are similarly unimpressive, leading some to question whether vitamin C, for example, might have pro-oxidant properties in vivo. We supplemented cold exposed (7+/-2 degrees C) female C57BL/6 mice over their lifespan with vitamin C (ascorbyl-2-polyphosphate), widely advocated and self administered to reduce oxidative stress, retard ageing and increase healthy lifespan. No effect on mean or maximum lifespan following vitamin C treatment or any significant impact on body mass, or on parameters of energy metabolism was observed. Moreover, no differences in hepatocyte and lymphocyte DNA oxidative damage or hepatic lipid peroxidation was seen between supplemented and control mice. Using a DNA macroarray specific for oxidative stress-related genes, we found that after 18 months of supplementation, mice exhibited a significantly reduced expression of several genes in the liver linked to free-radical scavenging, including Mn-superoxide dismutase. We confirmed these effects by Northern blotting and found additional down-regulation of glutathione peroxidase (not present on macroarray) in the vitamin C treated group. We suggest that high dietary doses of vitamin C are ineffective at prolonging lifespan in mice because any positive benefits derived as an antioxidant are offset by compensatory reductions in endogenous protection mechanisms, leading to no net reduction in accumulated oxidative damage.
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Affiliation(s)
- Colin Selman
- Aberdeen Centre for Energy Regulation and Obesity (ACERO), School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK.
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24
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Meyer CW, Neubronner J, Rozman J, Stumm G, Osanger A, Stoeger C, Augustin M, Grosse J, Klingenspor M, Heldmaier G. Expanding the body mass range: associations between BMR and tissue morphology in wild type and mutant dwarf mice (David mice). J Comp Physiol B 2006; 177:183-92. [PMID: 17009045 DOI: 10.1007/s00360-006-0120-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 08/23/2006] [Accepted: 08/25/2006] [Indexed: 11/27/2022]
Abstract
We sought to identify associations of basal metabolic rate (BMR) with morphological traits in laboratory mice. In order to expand the body mass (BM) range at the intra-strain level, and to minimize relevant genetic variation, we used male and female wild type mice (C3HeB/FeJ) and previously unpublished ENU-induced dwarf mutant littermates (David mice), covering a body mass range from 13.5 g through 32.3 g. BMR was measured at 30 degrees C, mice were killed by means of CO(2 )overdose, and body composition (fat mass and lean mass) was subsequently analyzed by dual X-ray absorptiometry (DEXA), after which mice were dissected into 12 (males) and 10 (females) components, respectively. Across the 44 individuals, 43% of the variation in the basal rates of metabolism was associated with BM. The latter explained 47% to 98% of the variability in morphology of the different tissues. Our results demonstrate that sex is a major determinant of body composition and BMR in mice: when adjusted for BM, females contained many larger organs, more fat mass, and less lean mass compared to males. This could be associated with a higher mass adjusted BMR in females. Once the dominant effects of sex and BM on BMR and tissue mass were removed, and after accounting for multiple comparisons, no further significant association between individual variation in BMR and tissue mass emerged.
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Affiliation(s)
- Carola W Meyer
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Karl-von-Frisch Strasse 8, 35043, Marburg, Germany.
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25
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White CR, Seymour RS. Does Basal Metabolic Rate Contain a Useful Signal? Mammalian BMR Allometry and Correlations with a Selection of Physiological, Ecological, and Life‐History Variables. Physiol Biochem Zool 2004; 77:929-41. [PMID: 15674767 DOI: 10.1086/425186] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2004] [Indexed: 11/03/2022]
Abstract
Basal metabolic rate (BMR, mL O2 h(-1)) is a useful measurement only if standard conditions are realised. We present an analysis of the relationship between mammalian body mass (M, g) and BMR that accounts for variation associated with body temperature, digestive state, and phylogeny. In contrast to the established paradigm that BMR proportional to M3/4, data from 619 species, representing 19 mammalian orders and encompassing five orders of magnitude variation in M, show that BMR proportional to M2/3. If variation associated with body temperature and digestive state are removed, the BMRs of eutherians, marsupials, and birds do not differ, and no significant allometric exponent heterogeneity remains between orders. The usefulness of BMR as a general measurement is supported by the observation that after the removal of body mass effects, the residuals of BMR are significantly correlated with the residuals for a variety of physiological and ecological variables, including maximum metabolic rate, field metabolic rate, resting heart rate, life span, litter size, and population density.
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Affiliation(s)
- Craig R White
- Department of Environmental Biology, School of Earth and Environmental Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia.
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26
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Kgwatalala PM, Nielsen MK. Performance of mouse lines divergently selected for heat loss when exposed to different environmental temperatures. II. Feed intake, growth, fatness, and body organs1. J Anim Sci 2004; 82:2884-91. [PMID: 15484938 DOI: 10.2527/2004.82102884x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mouse populations differing in metabolic rate have been developed through selection for high (MH) and low (ML) heat loss, along with the unselected controls (MC). Objectives of the study were to compare the MH, ML, and MC lines for feed intake, growth, body fatness, and organ weights when reared at 12, 22, and 31 degrees C, and investigate potential line x environment interactions. Feed intake was recorded weekly from 3 to 9 wk of age, and BW at 3, 6, and 9 wk of age. Body fat percent and organ weights were measured at 9 wk of age. No line x environment interactions were detected for any of the traits measured. The MH mice consumed more feed than ML mice from 5 to 9 wk of age. Between 8 and 9 wk of age, MH mice consumed 13% more feed than the ML mice, but they were relatively leaner (14.45 vs. 16.32% body fat); MC mice were intermediate for both traits. Mice in the cold environment consumed the greatest amount of feed, and those in the hot environment consumed the least. Males consumed more feed than females, and the difference was greater in the cold than in the hot environment. No differences in BW were found between the lines. Mice in the 22 degrees C environment were heavier than their age-matched counterparts in the other two environments, and males were heavier than females at all ages. Relative to BW, the three lines had similar tail length, body length, and liver weight. Mice in the cold environment had heavier spleens and livers than those in the hot environment but relatively shorter bodies and tails; the normal environment was intermediate for these traits. Results from this study indicate that selection to decrease maintenance requirements did not produce mice with any less ability to grow and perform under an array of environmental temperatures.
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Affiliation(s)
- P M Kgwatalala
- Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA
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Kgwatalala PM, DeRoin JL, Nielsen MK. Performance of mouse lines divergently selected for heat loss when exposed to different environmental temperatures. I. Reproductive performance, pup survival, and metabolic hormones1. J Anim Sci 2004; 82:2876-83. [PMID: 15484937 DOI: 10.2527/2004.82102876x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mouse populations differing in metabolic rate have been developed through selection for high (MH) and low (ML) heat loss, along with the unselected controls (MC). Objectives of the study were to compare the MH, ML, and MC lines for reproductive performance, pup survival, and metabolic hormones when reared at 12, 22, and 31 degrees C, and to search for line x environment interactions. Conception and litter size were recorded on the parent generation mice introduced to the environments at 11 wk of age and bred after a 3-wk acclimatization period. Survival of pups (preweaning to 3 wk; postweaning from 3 to 9 wk of age) was measured with continuous exposure in the designated environment from birth to the time of measurement. Corticosterone, triiodothyronine (T3), and thyroxine (T4) serum concentrations were measured on the parent generation after producing litters and on the pup generation at 9 wk. No line x environment interaction was detected for conception rate, preweaning mortality, postweaning survival, pup weaning weight, or body temperature. There were no differences in conception rate among lines and environments. Environments affected survival of pups, but there were no line differences. Rectal body temperatures were greater for MH than ML mice, and MC mice were intermediate; body temperature of mice did not differ among the environments. Lines differed significantly in litter size only in the 22 degrees C environment. No significant line differences were found for serum corticosterone or serum T3 or T4. Line x environment interaction was detected only for litter size and for serum corticosterone concentration in dams. Contrary to the other two lines, ML dam performance relative to MH and MC was not affected negatively by either of the thermal environments. Results from this study do not raise concern that selection to decrease maintenance requirements will produce livestock with any greater liability to cope and perform under an array of environmental temperatures.
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Affiliation(s)
- P M Kgwatalala
- Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA
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White CR. The influence of foraging mode and arid adaptation on the basal metabolic rates of burrowing mammals. Physiol Biochem Zool 2003; 76:122-34. [PMID: 12695993 DOI: 10.1086/367940] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2002] [Indexed: 11/03/2022]
Abstract
Two competing but nonexclusive hypotheses to explain the reduced basal metabolic rate (BMR) of mammals that live and forage underground (fossorial species) are examined by comparing this group with burrowing mammals that forage on the surface (semifossorial species). These hypotheses suggest that the low BMR of fossorial species either compensates for the enormous energetic demands of subterranean foraging (the cost-of-burrowing hypothesis) or prevents overheating in closed burrow systems (the thermal-stress hypothesis). Because phylogentically informed allometric analysis showed that arid burrowing mammals have a significantly lower BMR than mesic ones, fossorial and semifossorial species were compared within these groups. The BMRs of mesic fossorial and semifossorial mammals could not be reliably distinguished, nor could the BMRs of large (>77 g) arid fossorial and semifossorial mammals. This finding favours the thermal-stress hypothesis, because the groups appear to have similar BMRs despite differences in foraging costs. However, in support of the cost-of-burrowing hypothesis, small (<77 g) arid fossorial mammals were found to have a significantly lower BMR than semifossorial mammals of the similar size. Given the high mass-specific metabolic rates of small animals, they are expected to be under severe energy and water stress in arid environments. Under such conditions, the greatly reduced BMR of small fossorial species may compensate for the enormous energetic demands of subterranean foraging.
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Affiliation(s)
- Craig R White
- Department of Environmental Biology, Adelaide University, Adelaide, South Australia 5005, Australia.
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