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1.
Wang JM Zhang YM Wang DH 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2006,145(4):1703-553
The present study was designed to examine whether photoperiod alone was effective to induce seasonal regulations in physiology in root voles (Microtus oeconomus) from the Qinghai-Tibetan plateau noted for its extreme cold environment. Root voles were randomly assigned into either long photoperiod (LD; 16L:8D) or short photoperiod (SD; 8L:16D) for 4 weeks at constant temperature (20 degrees C). At the end of acclimation, SD voles showed lower body mass and body fat coupled with higher energy intake than LD voles. SD greatly enhanced thermogenic capacities in root voles, as indicated by elevated basal metabolic rate (BMR), nonshivering thermogenesis (NST), mitochondrial protein content and uncoupling protein-1 (UCP1) content in brown adipose tissue (BAT). Although no variations in serum leptin levels were found between SD and LD voles, serum leptin levels were positively correlated with body mass and body fat mass, and negatively correlated with energy intake and UCP1 content in BAT, respectively. To summarize, SD alone is effective in inducing higher thermogenic capacities and energy intake coupled with lower body mass and body fat mass in root voles. Leptin is potentially involved in the photoperiod induced body mass regulation and thermogenesis in root voles. 相似文献
2.
R. M. McDevitt J. R. Speakman 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1994,164(2):159-164
The thermogenic capacity of brown adipose tissue in winter- and summer-acclimatized short-tailed field voles (Microtus agrestis) was investigated by examining changes in mass of brown adipose tissue, the ratio of white adipose tissue to brown adipose
tissue, the concentration of the uncoupling protein (thermogenin) in whole depots (μg) and in mitochondrial mass (μg·mg-1) and the activity of cytochrome c oxidase in the depots (mmol·min-1). The concentration of thermogenin in winter-acclimatized voles (n=8), per brown adipose tissue depot and per mitochondrial mass, was significantly higher than in summer-acclimatized voles
(n=6). There was no significant difference in the level of cytochrome c oxidase activity between these two groups. Four groups
of winter-acclimatized voles (n=6 in each group) were exposed to 5°C for 10, 20, 50 and 100 days in a 14L:10D photoperiod. Body mass, brown adipose tissue
mass, white adipose tissue mass and basal metabolic rate were significantly positively related to the length of time cold
exposed up to 100 days. There was a significant inverse relationship between the ratio of white to brown adipose tissue mass
and the duration of cold exposure. There was no significant relationship between thermogenin concentration, either per depot
or in mitochondrial mass of brown adipose tissue, with the length of time cold exposed. The level of cytochrome c oxidase
activity increased significantly from control levels to a maximum after 10 days in the cold but decreased from 10 days onwards.
In winter-acclimatized M. agrestis, a 14L:10D photoperiod is not a sufficient stimulus to reduce thermogenic capacity during cold acclimation. Indeed, some
changes in the indirect parameters reflecting thermogenesis, notably the increase in basal metabolic rate and the decrease
in the ratio of white to brown adipose tissue mass, indicated that despite the long photophase the thermogenic capacity was
slightly further enhanced during the cold acclimation. 相似文献
3.
Chen JF Zhong WQ Wang DH 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2012,182(2):275-285
Small mammals inhabiting temperate and arctic regions exhibit annual adaptive adjustments in physiology, anatomy, and behavior.
No data on the physiology of Maximowicz’s voles (Microtus maximowiczii) are available at present. Here we examined the seasonal changes in body mass, food intake, thermogenic capacity, serum leptin
and thyroid hormone levels in wild-captured individuals from Inner Mongolian grassland, China. We further examined the effects
of photoperiod on these parameters. Energy intake, resting metabolic rate, nonshivering thermogenesis (NST), and serum tri-iodothyronine
(T3) levels increased while serum leptin and body mass decreased in the cold seasons. Serum T3 levels were positively correlated
with NST and uncoupling protein 1 (UCP1) contents in brown adipose tissue, and leptin levels were negatively correlated with
energy intake and resting metabolic rate. Furthermore, laboratory data showed these changes could be induced by short photoperiod
alone. Taken together, our results indicate that Maximowicz’s voles can increase thermogenic capacity and energy intake to
cope with cold stress. Serum leptin seems to be involved in the regulation of energy intake and changes in T3 level may be
important for the variations in NST and/or UCP1. Short photoperiod can serve as a seasonal cue for the winter acclimatization
of energy balance in free-living Maximowicz’s voles. 相似文献
4.
光照和温度对根田鼠褐色脂肪组织产热能力的影响 总被引:1,自引:1,他引:0
测定了根田鼠在室内驯化2周后褐色脂肪组织(BAT)的蛋白含量、线粒体蛋白含量和细胞色素C氧化酶活性的变化。动物进行如下4种处理:23℃,16L:8D;23℃,8L:16D;5℃,16L:8D和5℃,8L:16D.。结果表明,短光照可刺激根田鼠的BAT线粒体细胞色素C氧化酶的活性增加;低温驯化可导致根田鼠的BAT线粒体蛋白含量增加;短光照加低温可进一步促进酶的活性增加。结合个体水平的产热特点,说明根田鼠在产热能力的季节驯化过程中,光周期是一主要的季节调节信号,环境温度进一步增强光照的作用,环境温度和光周期共同作用以诱导其产热能力等方面的生理调节。研究结果支持了环境温度和光周期共同作用以调节动物产热变化的学说。 相似文献
5.
The present study was designed to examine whether photoperiod alone was effective to induce seasonal changes in physiology in voles (Eothenomys.) from the Hengduan Mountain region. Eothenomys miletus were randomly assigned into either long photoperiod (LD; 16L: 8D) or short photoperiod (SD; 8L: 16D) for 4 weeks at constant temperature (25 °C). At the end of acclimation, SD voles showed lower body mass and body fat coupled with higher energy intake than LD voles. SD greatly enhanced the thermogenic capacity of E. miletus, as indicated by an elevated nonshivering thermogenesis (NST), mitochondrial protein in brown adipose tissue (BAT); basal metabolic rate (BMR) was also raised. Although no variations in serum leptin levels were found between SD and LD voles, serum leptin levels were positively correlated with body mass and body fat mass, and negatively correlated with energy intake and UCP1 content in BAT, respectively. To summarize, SD alone is effective in inducing higher thermogenic capacities and energy intake coupled with lower body mass and body fat mass in root voles. Leptin is potentially involved in the photoperiod induced body mass regulation and thermogenesis in E. miletus. Our study shows that SD alone is effective. 相似文献
6.
Effects of cold,short day and melatonin on thermogenesis,body weight and reproductive organs in Alaskan red-backed voles 总被引:1,自引:0,他引:1
Dale D. Feist Carol F. Feist 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1986,156(5):741-746
Summary This study examined whether cold, short day or melatonin causes reproductive regression and stimulates nonshivering thermogenesis in a subarctic rodentClethrionomys rutilus. Red-backed voles born and raised at 23°C and 22 h light per day (LD 22: 2) at Fairbanks, Alaska (65°N) were exposed in one of six groups to: 1) long day (LD 22:2), 23°C, injected daily with melatonin or saline 2 h before lights out, 2) long day, 3°C, injected daily with melatonin or saline, 3) short day (LD 8:16), 23°C or 3°C. Voles were tested for nonshivering thermogenesis (NST) prior to and after 8 wk exposure. Body weight, testes weight and female reproductive tract weight were assessed after 8 wk in long day and 12 wk in short day.NST was not altered by short day or melatonin but cold (3°C) caused an increase in NST which was similar in long day and short day.Body weight of males and females was not affected by short day but was decreased by melatonin.Short day did not alter mean testes weight (about 20% voles regressed) but reduced mean female reproductive tract weight (more than 40% voles regressed). Melatonin reduced testes weight and female reproductive tract weight (more than 50% of voles of both sexes regressed).The results suggest that in northern red-backed voles: 1) the pineal does not mediate seasonal changes in thermogenic capacity, 2) the pineal may mediate reduction of body weight and regression of reproductive organs but, in addition to daylength, other cues or factors may be important, 3) populations may exhibit variability in sensitivity of reproduction to photoperiod which could allow for opportunistic breeding.Abbreviations
NST
nonshivering thermogenesis
-
NE
norepinephrine
-
RMR
resting metabolic rate 相似文献
7.
Environmental factors play an important role in the seasonal adaptation of body mass and thermogenesis in wild small mammals. In this study, we performed a factorial experiment (temperature x photoperiod) in which Brandt's voles and Mongolian gerbils were acclimated to different photoperiods (long photoperiod, 16L : 8D; short photoperiod, 8L : 16D) and temperatures (warm, 23 degrees C; cold, 5 degrees C) to test the hypothesis that photoperiod, temperature, or both together can trigger seasonal changes in serum leptin level, body mass, thermogenesis, and energy intake. Our data demonstrate that Brandt's voles showed a remarkable decrease in body mass in both the cold and a short photoperiod. However, no significant changes in body mass were found for gerbils exposed to similar conditions. The short photoperiod induced a decrease in serum leptin levels for both voles and gerbils that might contribute to an increase in energy intake. Furthermore, the short photoperiod induced an increase of uncoupling protein 1 (UCP1) content for both voles and gerbils, and cold can further enhance the increase in voles. No interactions between photoperiod and temperature were detected for the two species. Brandt's voles can decrease their body mass through changes in energy intake and expenditure, while Mongolian gerbils can keep body mass relatively stable by balancing energy metabolism under winterlike conditions. Leptin was potentially involved in the regulation of body mass and thermogenic capacity for the two species. 相似文献
8.
Mzilikazi N Lovegrove BG 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2006,176(1):75-84
The evolution of endothermy is thought to have been facilitated by the advent of endothermic energy sources such as brown
adipose tissue (BAT), the principal site of non-shivering thermogenesis (NST). In marsupials, heat is primarily produced through
shivering and NST in skeletal muscle because BAT is either absent or appears to be non-functional. The most basal group of
the eutherian lineage are the Afrotheria. Rock elephant shrews, Elephantulus myurus are amongst the smallest members of the Afrotheria and are also known to use exogenous passive heating. The aim of this study
was to determine whether the reliance on passive heating compromised the capacity for thermogenesis in E. myurus. We measured the thermogenic response to noradrenalin (NA) injection in E. myurus acclimated to short photoperiod. The thermogenic response at 25°C was 1.58 ml O2 g−1 h−1. We used phylogenetically independent analyses to establish how this thermogenic response compared to other eutherians that
display classical NST. The thermogenic response of E. myurus was not significantly different from phylogenetically independent allometric predictions. However, it is unclear whether
this thermogenic response is indicative of classical NST and molecular data are required to verify the presence of BAT and
UCPs in elephant shrews. 相似文献
9.
Brown adipose tissue is a major thermogenic effector of cold-induced nonshivering thermogenesis. Previous studies indicate that melatonin and/or short photo-period are involved in the increase in brown fat deposition seen in certain cold-acclimated rodents. The present study was undertaken, in part, to determine whether the pineal is a necessary component in the cold-induced increase in thermogenic capacity characteristic of the cold-acclimated laboratory rat. Under a 12L:12D light cycle, pinealectomized rats did not differ from sham-operated rats in their ability to increase brown fat deposition in the cold (5 °C). Moreover, in a subsequent set of experiments performed at 9 °C, intact rats maintained at a short photoperiod (9L:15D) exhibited the same degree of brown fat hypertrophy/hyperplasia as did those kept at a long photoperiod (15L:9D). These data thus indicate that: (a) the intact pineal is not necessary for the cold-induced increase in brown adipose tissue occurring in the cold-acclimated rat; and (b) photoperiod does not significantly modulate the magnitude of this increase. 相似文献
10.
Phenotypic plasticity of reproductive traits in response to food availability and photoperiod in white-footed mice (Peromyscus leucopus) 总被引:4,自引:0,他引:4
Changes in photoperiod, ambient temperature and food availability trigger seasonal acclimatization in physiology and behavior of many animals. In the present study, seasonal adjustments in body mass and in several physiological, hormonal, and biochemical markers were examined in wild-captured plateau pikas (Ochotona curzoniae) from the Qinghai-Tibetan plateau. Our results showed that plateau pikas maintained a relatively constant body mass throughout the year and showed no seasonal changes in body fat mass and circulating levels of serum leptin. However, nonshivering thermogenesis, cytochrome c oxidase activity, and mitochondrial uncoupling protein 1 (UCP1) contents in brown adipose tissues were significantly enhanced in winter. Further, serum leptin levels were positively correlated with body mass and body fat mass while negatively correlated with UCP1 contents. Together, these data suggest that plateau pikas mainly depend on increasing thermogenic capacities, rather than decreasing body mass, to cope with cold, and leptin may play a potential role in their thermogenesis and body mass regulation. 相似文献
11.
Polymeropoulos ET Jastroch M Frappell PB 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2012,182(3):393-401
The presence of nonshivering thermogenesis in marsupials is controversially debated. Survival of small eutherian species in
cold environments is crucially dependent on uncoupling protein 1 (UCP1)-mediated, adaptive nonshivering thermogenesis that
is executed in brown adipose tissue. In a small dasyurid marsupial species, the fat-tailed dunnart (Sminthopsis crassicaudata), an orthologue of UCP1 has been recently identified which is upregulated during cold exposure resembling adaptive molecular
adjustments of eutherian brown adipose tissue. Here, we tested for a thermogenic function of marsupial brown adipose tissue
and UCP1 by evaluating the capacity of nonshivering thermogenesis in cold-acclimated dunnarts. In response to an optimal dosage
of noradrenaline, cold-acclimated dunnarts (12°C) showed no additional recruitment of noradrenaline-induced maximal thermogenic
capacity in comparison to warm-acclimated dunnarts (24°C). While no differences in body temperature were observed between
the acclimation groups, basal metabolic rate was significantly elevated after cold acclimation. Therefore, we suggest that
adaptive nonshivering thermogenesis does not occur in this marsupial species despite the cold recruitment of oxidative capacity
and UCP1 in the interscapular fat deposit. In conclusion, the ancient UCP orthologue in marsupials does not contribute to
the classical nonshivering thermogenesis, and may exhibit a different physiological role. 相似文献
12.
Rose RW West AK Ye JM McCormick GH Colquhoun EQ 《Physiological and biochemical zoology : PBZ》1999,72(6):699-704
The Tasmanian bettong (Bettongia gaimardi, a marsupial) is a rat-kangaroo that increases nonshivering thermogenesis (NST) in response to norepinephrine (NE). This study attempted to assess whether brown adipose tissue (BAT), a specialized thermogenic effector, is involved in NST in the bettong. Regulatory NST, indicated by resting oxygen consumption (Vo2) of the whole body, was measured under conscious conditions at 20 degrees C with various stimuli: cold (4 degrees -5 degrees C) or warm (25 degrees C) acclimation, NE injection, and the beta3-adrenoceptor agonist (BRL) 37344. In line with the functional studies in vivo, the presence of BAT was evaluated by examining the expression of the uncoupling protein 1 (UCP1) with both rat cDNA and oligonucleotide probes. Both NE and BRL 37344 significantly stimulated NST in the bettong. After cold acclimation of the animals (at 4 degrees -5 degrees C for 2 wk), the resting Vo2 was increased by 15% and the thermogenic effect of NE was enhanced; warm-acclimated animals showed a slightly depressed response. However, no expression of UCP1 was detected in bettongs either before or after cold exposure (2 wk). These data suggest that the observed NST in the marsupial bettong is not attributable to BAT. 相似文献
13.
14.
为阐明小型哺乳动物被毛的季节性变化及其在能量代谢和体温调节中的作用,测定了季节性驯化,以及不同光周期和温度驯化的黑线仓鼠的被毛重量、体温和能量收支。结果显示: (1)冬季黑线仓鼠的被毛重量和产热显著高于夏季;(2)短光照(8L∶16D)和低温(5℃ ) 对被毛生长的影响不显著; (3)与室温组(21℃ )相比,低温组(5℃ )摄入能、基础代谢率(BMR)、非颤抖性产热(NST) 、褐色脂肪组织细胞色素c 氧化酶活性和热传导率显著增加,而暖温组(30℃ )显著降低; (4)室温和低温下,剃毛导致摄入能、BMR、NST 和热传导率显著增加;结果表明:被毛的作用与环境温度有关,低温下被毛降低了能量需求,增强了动物应对低温环境的适应能力;被毛的适应性变化是独居的野生小型哺乳动物应对环境温度季节性波动的主要适应策略之一,在其能量代谢和体温调节中具有重要作用和意义。 相似文献
15.
16.
Brandt's voles (Lasiopodomys brandti) exposed to cold (5±1 °C) or warm (23±1 °C) showed some physiological and biochemical variations which might be important in adaptation to their environments. Cold acclimation induced increases in resting metabolic rate (RMR) and the serum triiodothyronine (T3) level, the state-4 respiration of liver and muscle mitochondria were activated after 7 days when animals exposed to cold, and the activity of cytochrome c oxidase (COX) of liver and muscle mitochondria tended to rise with cold exposure. RMR and T3 level decreased during warm acclimation. The state-4 respiration of liver mitochondria declined after 3 days and muscle after 7 days when animals exposed to warm, and the activities of COX of liver and muscle mitochondria tended to decrease with warm acclimation. The cold activation of liver and muscle mitochondrial respiration (regulated by T3) was one of the cytological mechanisms of elevating RMR. Both state-4 respiration and COX activity of brown adipose tissue (BAT) mitochondria increased significantly during cold acclimation and decreased markedly after acclimated to warm. The uncoupling protein 1 (UCP1) contents in BAT increased after exposure to cold and decreased after warm acclimation. Nonshivering thermogenesis (NST) plays an important role in the process of thermoregulation under cold acclimation for Brandt's voles. Changes in thermogenesis is a important way to cold adaptation for Brandt's voles in natural environments. 相似文献
17.
Photoperiod and temperature affect reproductive and nonreproductive functions in male prairie voles (Microtus ochrogaster) 总被引:1,自引:0,他引:1
Adult male prairie voles (Microtus ochrogaster) were housed for 10 wk and exposed to long (16L:8D) or short (8L:16D) photoperiods at 21 degrees or 5 degrees C. Maintenance in short day lengths reduced testicular, epididymal, and seminal vesicle mass and also significantly depressed spermatogenic activity. Cold ambient temperature further suppressed gonadal size in voles exposed to short days. Several pelage characteristics were affected by photoperiod, but not by temperature. Increased fur density, fur depth, and length of guard hair and underhair were observed in voles exposed to short days. Intrascapular brown fat and gonadal fat pad mass as well as body mass were significantly less in voles housed in cold temperatures than in voles exposed to warm ambient temperatures; photoperiod did not affect these parameters. Approximately 30% of the male voles exposed to short days maintained their reproductive systems, yet they clearly processed photoperiodic information; all short-day males, regardless of reproductive condition, had comparable winter pelage development. Our results suggest that in prairie voles, photoperiod may be a predictive cue for reproductive function in nature; however, it appears that pelage development is a more obligatory response to photoperiod than is reproduction. 相似文献
18.
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
19.
Król E Duncan JS Redman P Morgan PJ Mercer JG Speakman JR 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2006,176(2):153-163
We have previously shown that cold-acclimated (8°C) male field voles (Microtus agrestis) transferred from short (SD, 8:16 h L:D) to long photoperiod (LD, 16:8 h L:D) exhibit increases in body mass, adiposity and
food intake. To assess whether these increases were associated with decreased leptin sensitivity, we infused LD and SD voles
with physiological doses of murine leptin (or saline) delivered peripherally for 7 days via mini-osmotic pumps. Measurements
were made of body mass (weight-reducing effect of leptin), food intake (anorectic effect of leptin) and gene expression of
uncoupling protein 1 (UCP1) in brown adipose tissue (BAT) (thermogenic effect of leptin). The SD animals were sensitive to
the weight-reducing effects of leptin (mean body mass decrease of 1.2 g over 7 days) and appetite-reducing effect of leptin
(mean food intake decrease of 2.5 g over 7 days), whereas LD voles were resistant to the hormone treatment. The switch from
a leptin-sensitive to leptin-resistant state appears to act as a desensitisation mechanism that allows voles transferred from
SD to LD to ignore elevated leptin levels generated by increased body fat and accumulate adipose tissue without stimulating
compensatory changes opposing the weight gain. Neither SD nor LD voles responded to infusion of leptin by changes in BAT UCP1
gene expression, suggesting dissociation of anorectic and thermogenic effects of leptin, possibly related to chronic cold
exposure. Our results indicate that cold-acclimated voles show photoperiod-regulated changes in leptin sensitivity and may
provide an attractive model for elucidating molecular mechanisms of leptin resistance. 相似文献
20.
R. M. McDevitt J. R. Speakman 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1996,166(4):286-293
We investigated the changes that occurred in basal and noradrenaline-induced metabolic rate, body temperature and body mass in short-tailed field voles,Microtus agrestis, during exposure to naturally increasing photoperiod and ambient temperature. These parameters were first measured in winter-acclimatized voles (n=8) and then in the same voles which had been allowed to seasonally acclimatize to photoperiod and ambient temperature (6 months later). Noradrenaline induced metabolic rate, basal metabolic rate and nonshivering thermogenesis were significantly higher in winter-acclimatized compared to summer-acclimatized voles. There was a significant positive relationship between basal metabolic rate and noradrenaline-induced metabolic rate. Body mass was significantly higher in summer-acclimatized compared to winter-acclimatized voles. There was a significant positive relationship between body mass and noradrenaline-induced metabolic rate in both winter-acclimalized and summer-acclimatized voles; however, there was no relationship between basal metabolic rate and body mass in either seasonal group of voles. Body temperature after measurements of basal metabolic rate was not significantly different in the seasonal cohorts of voles. However, body temperature was significantly higher in winter-acclimatized compared to summer-acclimatized voles after injection of noradrenaline. Previously we have found that a long photoperiod was not a sufficient stimulus to reduce thermogenic capacity in winter-acclimatized voles during cold exposure, since basal metabolic rate increased to compensate for a reduction in regulatory nonshivering thermogenesis. Here we found that a combination of increased ambient temperature and photoperiod did significantly reduce thermogenic capacity in winter-acclimatized voles. This provided evidence that the two aspects of non-shivering thermogenesis, obligatory and regulatory, are stimulated by different exogenous cues. Summer acclimatization in the shorttailed field vole is manifest as a significant decrease in both basal and noradrenaline-induced metabolic rate, combined with a significant increase in body mass.Abbreviations
ANCOV A
analysis of covariance
-
BAT
brown adipose tissue
-
BM
body mass
-
BMR
basal metabolic rate
-
NST
non-shivering thermogenesis
-
NA
noradrenaline
- V
the maximum V recorded following mass specific injection of noradrenaline
- V
the maximum V recorded following mass specific injection of saline
-
T
a
ambient temperature
-
T
b
rectal body temperature
-
T
1c
lower critical temperature
-
UCP
uncoupling protein
- V
oxygen consumption 相似文献