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1.
动物能量代谢的生理生态特征与物种的分布和丰富度密切相关,基础代谢率(basal metabolic rate,BMR)是恒温动物维持正常生理机能的最小产热速率,是内温动物能量预算的重要组成部分.该文以白头鹎(Pycnonotus sinensis)为研究对象,分别在冬季和夏季测定了白头鹎的体重、BMR、肝脏和肌肉的线粒体蛋白质含量、线粒体呼吸及细胞色素C氧化酶(cytochrome c oxidase,COX)活力及血清中甲状腺素(T4)及三碘甲腺原氨酸(T3)含量的变化,从细胞和酶学水平上解释白头鹎基础产热的季节适应规律.耗氧量采用封闭式流体压力呼吸测定仪测定,肝脏和肌肉的线粒体状态4呼吸及COX活力采用铂氧电极-溶氧仪测定.结果显示:白头鹎的体重和BMR冬季显著高于夏季;肝脏和肌肉的线粒体呼吸,以及肝脏和肌肉的COX活力冬季明显高于夏季;血清T3浓度冬季较高,夏季较低.这些结果表明:在野外自然条件下,肝脏和肌肉在细胞水平产热能力的提高和血清T3含量的增加是白头鸭BMR增加的细胞学机制之一,同时是白头鹎抵御冬季寒冷的一种重要方式.  相似文献   

2.
甲状腺激素对白头鹎基础产热的影响   总被引:2,自引:0,他引:2  
甲状腺激素对动物的基础产热有调节作用,甲状腺活性的增加往往与基础代谢的增加相伴行。通过每日饲喂甲状腺素(T4)研究了甲状腺机能亢进对白头鹎(Pycnonotus sinensis)代谢产热的影响。代谢率的测定采用封闭式流体压力呼吸计测定,细胞色素C氧化酶(COX)采用铂氧电极-溶氧仪测定,反应温度为30℃,肝脏和肌肉的线粒体状态4呼吸采用铂氧电极-溶氧仪测定,反应温度为30℃,线粒体蛋白的测定以牛血清蛋白作为标准,采用Folin-phenol方法,测定肝脏和肌肉组织的蛋白质含量。与对照组相比,甲亢组的基础代谢率(BMR)明显升高;肝脏及肌肉组织状态4呼吸增加;肝脏和肌肉线粒体的COX活力升高。  相似文献   

3.
长爪沙鼠季节性产热特征比较   总被引:3,自引:3,他引:0  
蔡理全  黄晨西 《兽类学报》1998,18(3):215-218
与夏季相比、冬季长爪沙鼠的静止代谢率和非颤抖性产热显著升高;褐色脂肪组织线粒体的细胞色素C氧化酶与α-磷酸甘油氧化酶活力升高,组织总蛋白质及线粒体蛋白质含量增加,而组织的脂肪含量减少;血清T3含量和T3/T4值都显著增加。但是肝脏的各项产热指标变化不显著、表明褐色脂肪组织的产热功能具有季节波动性,是长爪沙鼠适应性产热的主要来源器官.  相似文献   

4.
燕雀和麻雀代谢产热及消化道形态特征比较   总被引:2,自引:3,他引:2  
于 2 0 0 3年 4~ 5月在黑龙江省齐齐哈尔市地区以 1 0只燕雀 (Fringillamontifringilla)和 9只麻雀(Passermontanus)的耗氧量、肝脏和肌肉的线粒体呼吸、肝脏和肌肉的细胞色素C氧化酶活性及消化道形态特征等为指标 ,探讨了燕雀和麻雀代谢产热及消化道形态的差异。燕雀的代谢率、肝脏和肌肉的线粒体呼吸及细胞色素C氧化酶活性均显著低于麻雀 ;而消化道总长度及小肠长度均明显高于麻雀。表明选择压力的不同塑造了燕雀和麻雀对环境的适应对策不同  相似文献   

5.
中缅树鼩的非颤抖性产热及细胞呼吸特征   总被引:5,自引:0,他引:5  
中缅树鼩(Tupaia belangeri chinensis)是东南亚树鼩中分布最北的一个种。在热中性区内的非颤抖性产热(nonshivering thermogenesis NST)分别为2.57±0.21(冬)和2.21±0.12(夏)mlO_2/(g·h);分别为体重预期值的75.9%和61.2%,两者不仅冬季显著高于夏季,而且亦高于典型的热带种类,但低于温带类群。褐色脂肪组织(brown adipose tissue,BAT)的重量冬季为0.622±0.015 S,夏季0.532±0.80 g,冬季也显著高于夏季;同时,BAT总蛋白含量、线粒体蛋白含量以及细胞α-磷酸甘油氧化酶和细胞色素C氧化酶活性,冬季也显著高于夏季,但增加的比例较温带种类低;而肝脏细胞的上述指标及线粒体状态Ⅲ、状态Ⅳ呼吸等,冬夏两季均无显著差异。因此,中缅树鼩的NST和细胞产热能力介于热带与温带类群之间,显示出向温带类型过渡的趋势。  相似文献   

6.
树麻雀代谢率和器官重量在季节驯化中表型的可塑性变化   总被引:1,自引:0,他引:1  
柳劲松  李铭 《动物学报》2006,52(3):469-477
动物能量代谢的生理生态特征与物种的分布和丰富度密切相关,基础代谢率(BMR)是内温动物能量预算的重要组成部分。北温带的小型鸟类,通过增加产热来适应低温环境。增加BMR的基础之一是中心器官(代谢机器)发生明显的变化。本研究中我们测定了树麻雀(Passermontanus)的BMR、体重和各器官的重量,分析了麻雀各器官的季节性变化及与BMR的关系。方差分析表明:麻雀的BMR存在明显的季节性变化,在冬季和秋季较高。麻雀内部器官的变化同样有明显的季节性,冬季和秋季麻雀的肝脏、心脏、肌胃、小肠、直肠和整体消化道的重量,都有明显的增加。相关分析表明:麻雀的BMR与肝脏、心脏和消化道等内部器官存在明显的相关性。我们的结果验证了“中心限制假说”,即麻雀体内存在着与BMR相关的“代谢机器”,中心器官是提高麻雀BMR的基础之一。  相似文献   

7.
冷驯化条件下大绒鼠的产热和能量代谢特征   总被引:7,自引:0,他引:7  
本文主要研究了冷驯化(5℃±1℃)条件下,大绒鼠(Eothenomys miletus)的能量收支、基础代谢率(BMR)、非颤抖性产热(NST)和肝脏线粒体呼吸.结果表明:随着冷驯化的进行,大绒鼠的体重、体温降低;摄入能、消化能、可代谢能增加;BMR和NST增加;肝脏线粒体呼吸状态Ⅲ呼吸先增加,28天后趋于平稳;线粒体状态Ⅳ呼吸先增加,28天后下降.说明在冷驯化条件下,大绒鼠采取适当降低体重和体温、增加能量摄入、增加BMR和NST产热的对策来维持能量平衡  相似文献   

8.
中缅树Qu的非颤抖性产热及细胞呼吸特征   总被引:4,自引:0,他引:4  
中缅树qu(Tupaia belangeri chinensis)是东南亚树qu中分布最北的一个种。在热中性区内的非颤抖性产热(nonshivering thermogenesis NST)分别为2.57±0.21(冬)和2.21±0.12(夏)mlO[2]/(g·h);分别为体重预期值的75.9%和61.2%,两者不仅冬季显著高于夏季,而且亦高于典型的热带种类,但低于温带类群。褐色脂肪组织(brown adipose tissue,BAT)的重量冬季为0.622±0.015 g,夏季0.532±0.80 g,冬季也显著高于夏季;同时,BAT总蛋白含量、线粒体蛋白含量以及细胞α-磷酸甘油氧化酶和细胞色素C氧化酶活性,冬季也显著高于夏季,但增加的比例较温带种类低;而肝脏细胞的上述指标及线粒体状态Ⅲ、状态Ⅳ呼吸等,冬夏两季均无显著差异。因此,中缅树qu的NST和细胞产热能力介于热带与温带类群之间,显示出向温带类型过渡的趋势。  相似文献   

9.
黄晨西  林琳  李庆芬 《兽类学报》2006,26(4):346-353
本文通过测定静止代谢率(RMR)、非颤抖性产热(NST)、线粒体呼吸酶、脂肪代谢酶活力、褐色脂肪组织(BAT)线粒体GTP结合能力、下丘脑促甲状腺激素释放激素(TRH)和促肾上腺激素释放激素(CRH)等指标,探讨短光照对达乌尔黄鼠产热的诱导和调节。结果表明,温暖(22℃)短光照(8D∶6L)组,达乌尔黄鼠的RMR、NST、肝脏和BAT线粒体细胞色素C氧化酶活力以及BAT线粒体GTP结合能力均明显高于温暖长光照(16D∶8L)组中的动物,而体重、BAT重量、肝细胞呼吸、BATα-磷酸甘油氧化酶活力则没有明显变化。短光照组黄鼠下丘脑TRH水平显著高于长光照组,而血清中三碘甲腺原氨酸(T3)及甲状腺素(T4)浓度、T3/T4以及BAT中T4-5’脱碘酶的活性没有明显变化。短光照组黄鼠下丘脑CRH水平显著高于对照组,而肾上腺皮质酮含量无明显变化。结果表明短光照能够诱导达乌尔黄鼠产热增加,主要是通过激活细胞色素C氧化酶活性和增加BAT中解偶联蛋白浓度;短光照可能激活下丘脑TRH和CRH,但它们没有直接诱导产热增加,推测其增加了黄鼠潜在的产热能力。  相似文献   

10.
小型哺乳动物通过产热能力的调整来应对环境的胁迫。为探究外源瘦素对不同地区大绒鼠(Eothenomys miletus)适应性产热的影响,选取云南昆明和大理地区捕获的大绒鼠各14只,置于25℃±1℃,光周期为12L∶12D的环境中,每日腹腔注射瘦素,持续28 d。以LT502电子天平每两天测定大绒鼠的体重,采用食物平衡法每两天测定大绒鼠摄食量,以便携式呼吸代谢测量系统每7天测定静止代谢率(RMR)、非颤抖性产热(NST)。第28天处死动物后,采用酶联免疫吸附法测定线粒体蛋白含量、线粒体细胞色素c氧化酶(COX)活性、解偶联蛋白1(UCP1)含量、血清三碘甲状腺原氨酸(T3)、甲状腺素(T4)、瘦素水平以及促甲状腺激素释放激素(TRH)和促肾上腺皮质激素释放激素(CRH)水平。结果表明,注射瘦素后昆明和大理地区大绒鼠的体重和摄食量显著降低,RMR和NST增强,肝脏中线粒体蛋白含量和COX活性,褐色脂肪组织(BAT)中COX活性和UCP1含量,及血清T3、T4、T3/T4比值、TRH和CRH浓度均增加。瘦素水平与体重、摄食量呈负相关,血清T3水平与NST和UCP1含量呈正相关。此外,注射前昆...  相似文献   

11.
Metabolic rates of mammals presumably increased during the evolution of endothermy, but molecular and cellular mechanisms underlying basal metabolic rate (BMR) are still not understood. It has been established that mitochondrial basal proton leak contributes significantly to BMR. Comparative studies among a diversity of eutherian mammals showed that BMR correlates with body mass and proton leak. Here, we studied BMR and mitochondrial basal proton leak in liver of various marsupial species. Surprisingly, we found that the mitochondrial proton leak was greater in marsupials than in eutherians, although marsupials have lower BMRs. To verify our finding, we kept similar-sized individuals of a marsupial opossum (Monodelphis domestica) and a eutherian rodent (Mesocricetus auratus) species under identical conditions, and directly compared BMR and basal proton leak. We confirmed an approximately 40 per cent lower mass specific BMR in the opossum although its proton leak was significantly higher (approx. 60%). We demonstrate that the increase in BMR during eutherian evolution is not based on a general increase in the mitochondrial proton leak, although there is a similar allometric relationship of proton leak and BMR within mammalian groups. The difference in proton leak between endothermic groups may assist in elucidating distinct metabolic and habitat requirements that have evolved during mammalian divergence.  相似文献   

12.
To preserve thermoneutrality, cold exposure is followed by changes in energy expenditure and basal metabolic rate (BMR). Because nitric oxide (NO) modulates mitochondrial O(2) uptake and energy levels, we analyzed cold effects (30 days at 4 degrees C) on rat liver and skeletal muscle mitochondrial NO synthases (mtNOS) and their putative impact on BMR. Cold exposure delimited two periods: A (days 1-10), with high systemic O(2) uptake and weight loss, and B (days 10-30), with lower O(2) uptake and fat deposition. mtNOS activity and expression decreased in period A and then increased in period B by 60-100% in liver and skeletal muscle (P < 0.05). Conversely, mitochondrial O(2) uptake remained initially high in the presence of l-arginine and later fell by 30-50% (P < 0.05). On this basis, the estimated fractional contribution of liver plus muscle to total BMR varied from 40% in period A to 25% in period B. The transitional modulation of mtNOS in rat cold acclimation could participate in adaptive responses that favor calorigenesis or conservative energy-saving mechanisms.  相似文献   

13.
The aerobic capacity model postulates that high basal metabolic rates (BMR) associated with endothermy evolved as a correlated response to the selection on maximum, peak metabolic rate Vo2max. Furthermore, the model assumes that BMR and Vo2max are causally linked, and therefore, evolutionary changes in their levels cannot occur independently. To test this, we compared metabolic and anatomical correlates of selection for high and low body mass-corrected BMR in males of laboratory mice of F18 and F19 selected generations. Divergent selection resulted in between-line difference in BMR equivalent to 2.3 phenotypic standard deviation units. Vo2max elicited by forced swimming in 20 degrees C water was higher in the low BMR than high BMR line and did not differ between the lines when elicited by exposure to heliox at -2.5 degrees C. Moreover, the magnitude of swim- and heliox-induced hypothermia was significantly smaller in low BMR mice, whereas their interscapular brown adipose tissue was larger than in high BMR mice. Our results are therefore at variance with the predictions of aerobic capacity model. The selection also resulted in correlated response in food consumption (C) and masses of metabolically active internal organs: kidneys, liver, small intestine, and heart, which fuel maximum, sustained metabolic rate (SusMR) rather than Vo2max. These correlated responses were strong enough to claim the existence of positive, genetic correlations between BMR and the mass of viscera as well as C. Thus, our findings support the suggestion that BMR evolved as a correlated response to selection for SusMR, not Vo2max. In functional terms BMR should therefore be interpreted as a measure of energetic costs of maintenance of metabolic machinery necessary to sustain high levels of energy assimilation rate.  相似文献   

14.
Both basal metabolic rate (BMR) and maximum lifespan potential (MLSP) vary with body size in mammals and birds and it has been suggested that these are mediated through size-related variation in membrane fatty acid composition. Whereas the physical properties of membrane fatty acids affect the activity of membrane proteins and, indirectly, an animal’s BMR, it is the susceptibility of those fatty acids to peroxidation which influence MLSP. Although there is a correlation between body size and MLSP, there is considerable MLSP variation independent of body size. For example, among bird families, Galliformes (fowl) are relatively short-living and Psittaciformes (parrots) are unusually long-living, with some parrot species reaching maximum lifespans of more than 100 years. We determined BMR and tissue phospholipid fatty acid composition in seven tissues from three species of parrots with an average MLSP of 27 years and from two species of quails with an average MLSP of 5.5 years. We also characterised mitochondrial phospholipids in two of these tissues. Neither BMR nor membrane susceptibility to peroxidation corresponded with differences in MLSP among the birds we measured. We did find that (1) all birds had lower n-3 polyunsaturated fatty acid content in mitochondrial membranes compared to those of the corresponding tissue, and that (2) irrespective of reliance on flight for locomotion, both pectoral and leg muscle had an almost identical membrane fatty acid composition in all birds.  相似文献   

15.
Temperature is an important environmental cue for the regulation of thermogenesis in small birds. We tested the hypothesis that a small passerine, the Chinese bulbul Pycnonotus sinensis can decrease thermogenesis in response to warmer temperatures by decreasing body mass, the organ mass and changing physiological and biochemical processes in the liver and muscle. Captive Chinese bulbuls decreased in body mass and basal metabolic rate (BMR) during 4 weeks of acclimation to 30±1 °C. They also showed a decrease in liver, kidney and small intestine mass and reduced mitochondrial state-4 respiration and cytochrome C oxidase (COX) activity in the liver and muscle compared to 10±1 °C. Furthermore, BMR was positively correlated with body mass, organ mass (liver, kidney, small intestine and entire digestive tract), and mitochondrial state-4 respiration and cytochrome C oxidase (COX) activity in the liver and muscle. These results indicate that changes in body mass, organ mass and respiratory enzyme activity are mechanisms by which Chinese bulbuls adapt to warmer temperatures. The data support the hypothesis that such physiological flexibility is ubiquitous in birds.  相似文献   

16.
Comparative analyses of avian energetics often involve the implicit assumption that basal metabolic rate (BMR) is a fixed, taxon-specific trait. However, in most species that have been investigated, BMR exhibits phenotypic flexibility and can be reversibly adjusted over short time scales. Many non-migrants adjust BMR seasonally, with the winter BMR usually higher than the summer BMR. The data that are currently available do not, however, support the idea that the magnitude and direction of these adjustments varies consistently with body mass. Long-distance migrants often exhibit large intra-annual changes in BMR, reflecting the physiological adjustments associated with different stages of their migratory cycles. Phenotypic flexibility in BMR also represents an important component of short-term thermal acclimation under laboratory conditions, with captive birds increasing BMR when acclimated to low air temperatures and vice versa. The emerging view of avian BMR is of a highly flexible physiological trait that is continually adjusted in response to environmental factors such as temperature. The within-individual variation observed in avian BMR demands a critical re-examination of approaches used for comparisons across taxa. Several key questions concerning the shapes and other properties of avian BMR reaction norms urgently need to be addressed, and hypotheses concerning metabolic adaptation should explicitly account for phenotypic flexibility.  相似文献   

17.
Physiological changes due to aging are intensively studied as they have far-reaching implications for the mechanistic and evolutionary theories of senescence. In this respect, metabolic rate has been suggested to play a role for the deterioration and damage of cells and tissues with age, partly due to the generation of reactive oxygen species. To mitigate such damage, individuals can be predicted to reduce basal metabolic rate (BMR) with age. This prediction has been verified in humans and some laboratory animals but never in wild animal populations. We analyzed the change in BMR within individuals across years in two wild populations of great tit (Parus major) differing in BMR. Great tits, living under stressful conditions towards the northern limit of their distribution, decreased their BMR as they aged whereas no such decrease was found in a southern population. Thus, we found a clear decline only in the population with the highest BMR levels. This study provides the first evidence of an age-related decline in BMR for a wild homeotherm.  相似文献   

18.
Broad-scale comparisons of birds indicate the possibility of adaptive modification of basal metabolic rate (BMR) and total evaporative water loss (TEWL) in species from desert environments, but these might be confounded by phylogeny or phenotypic plasticity. This study relates variation in avian BMR and TEWL to a continuously varying measure of environment, aridity. We test the hypotheses that BMR and TEWL are reduced along an aridity gradient within the lark family (Alaudidae), and investigate the role of phylogenetic inertia. For 12 species of lark, BMR and TEWL decreased along a gradient of increasing aridity, a finding consistent with our proposals. We constructed a phylogeny for 22 species of lark based on sequences of two mitochondrial genes, and investigated whether phylogenetic affinity played a part in the correlation of phenotype and environment. A test for serial independence of the data for mass-corrected TEWL and aridity showed no influence of phylogeny on our findings. However, we did discover a significant phylogenetic effect in mass-corrected data for BMR, a result attributable to common phylogenetic history or to common ecological factors. A test of the relationship between BMR and aridity using phylogenetic independent constrasts was consistent with our previous analysis: BMR decreased with increasing aridity.  相似文献   

19.
Debate on the mechanism(s) responsible for the scaling of metabolic rate with body size in mammals has focused on why the maximum metabolic rate (VO2max ) appears to scale more steeply with body size than the basal metabolic rate (BMR). Consequently, metabolic scope, defined as VO2max/BMR, systematically increases with body size. These observations have led some to suggest that VO2max, and BMR are controlled by fundamentally different processes, and to discount the generality of models that predict a single power-law scaling exponent for the size dependence of the metabolic rate. We present a model that predicts a steeper size dependence for VO2max than BMR based on the observation that changes in muscle temperature from rest to maximal activity are greater in larger mammals. Empirical data support the model's prediction. This model thus provides a potential theoretical and mechanistic link between BMR and VO2 max.  相似文献   

20.
Objective : The contribution of basal metabolic rate (BMR) to weight gain susceptibility has long been debated. We wanted to examine whether BMR changes in a linear fashion with overfeeding. Our hypothesis was that BMR does not increase linearly with 1000‐kcal/d overfeeding in lean healthy subjects over 8 weeks. The null hypothesis states that BMR increases linearly with 1000‐kcal/d overfeeding in lean healthy subjects. Research Methods and Procedures : Initially, 16 lean healthy sedentary subjects completed 2 weeks of weight maintenance feeding at the General Clinical Research Center. The subjects were then overfed by 1000 kcal/d over 8 weeks. BMR was measured under standard conditions each week using indirect calorimetry. Results : Baseline BMR was 1693 ± 154.5 kcal/d. BMR increased from 1711 ± 201.3 kcal/d at week 1 of overfeeding to 1781 ± 171.65 kcal/d at the second week of overfeeding (p = 0.05). BMR fell during the third week of overfeeding to 1729 ± 179.5 kcal/d (p = 0.05). After 5 weeks of overfeeding, BMR reached a plateau. Thereafter, there was no further change. Comparison of BMR with weeks of overfeeding was significantly different compared with the linear model (p < 0.05). Discussion : Increases in BMR in lean sedentary healthy subjects with 1000‐kcal/d overfeeding are not linear over 8 weeks. There seems to be a short‐term increase in BMR in the first 2 weeks of overfeeding that is not representative of longer‐term changes.  相似文献   

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