Effects of Energy Expenditure and Ucp 1 on Photoperiod‐Induced Weight Gain in Collared Lemmings

We examined the effect of increasing photoperiod, at a constant low temperature, on the body mass and energy budget of the bank vole Clethrionomys glareolus. Simultaneously, we determined the hypothalamic gene expression of neuropeptides and receptors known to be involved in short-term energy balance. Despite an increase in body mass (approximately 10% of initial mass), we found no significant changes in any energetic parameters (food intake, energy assimilation rate, resting metabolic rate and total daily energy expenditure by doubly-labelled water). Apparent energy assimilation efficiency was higher in voles exposed to long-days (LD) compared to short-days (SD). Surprisingly, gene expression of corticotrophin releasing factor (CRF; in the paraventricular nucleus), and the melanocortin-3 receptor (in the arcuate nucleus), both known to be involved in appetite suppression and elevation of energy expenditure in short-term energy balance, were higher in voles kept in LD compared to SD. CRF expression was also elevated in females compared to males. These paradoxical data suggest an alternative mechanism for the control of seasonal body mass changes compared to short-term body mass changes, and between male and female voles. Furthermore, they highlight the need for studies to perform simultaneous measurements at both the molecular and whole animal levels.

Section: Hypothalamic Neuropeptide and Receptor Gene Expressionsupporting

confidence: 77%

Photoperiodic effects on body mass, energy balance and hypothalamic gene expression in the bank vole

Peacock

Król

Moar³

et al. 2004

“…In adults of most rodent species, SD enhances UCP1 content in BAT as reported for common spiny mice (Acomys cahirinus) (Kronfeld-Schor et al, 2000), Siberian hamsters ) and Brandt's voles (Zhao and Wang, 2005). In the present study, the response to postweaning photoperiod was similar to that described in the abovementioned results but opposite to the SD-induced declines in UCP1 mRNA level and resting energy expenditure in collared lemmings (Powell et al, 2002). Of particular interest in our study was that we found evidence that SD both before and after weaning significantly increased UCP1 content; SS voles had the highest content of all groups (Fig.·5).…”

Section: Effects Of Photoperiod History On Thermogenic Capacitysupporting

confidence: 76%

“…Studies concerning the effects on energy expenditure of photoperiod history have been conducted predominantly in adult animals. Powell et al (Powell et al, 2002) found that when long photoperiod (LD) collared lemmings (Dicrostonyx groenlandicus) were exposed to a short photoperiod (SD), resting energy expenditure and uncoupling protein 1 (UCP1) mRNA levels in brown adipose tissue (BAT) decreased. In some species such as Siberian hamsters (Phodopus sungorus), SD acclimation increased non-shivering thermogenesis (NST) and UCP1 content .…”

Section: Introductionmentioning

confidence: 99%

Effects of photoperiod history on body mass and energy metabolism in Brandt's voles (Lasiopodomys brandtii)

Zhong

Wang

2007

SUMMARY Many small mammals respond to seasonal changes in photoperiod via alterations in morphology, physiology and behaviour. In the present study, we tested the hypothesis that the preweaning (from embryo to weaning) photoperiod experience can affect subsequent development in terms of body mass and thermogenesis. Brandt's voles (Lasiopodomys brandtii) were gestated and reared to weaning under either a short (SD, 8 h:16 h L:D) or a long photoperiod (LD, 16 h:8 h L:D) at a constant ambient temperature (23°C). At weaning, male juveniles were either maintained in their initial photoperiod or transferred to the alternative photoperiod for 8 weeks. Postweaning SD voles had a lower body mass but higher thermogenic capacity compared with LD voles. At the same time, preweaning photoperiod conditions had long-lasting effects on thermogenic capacity later in life. Serum leptin concentration was positively correlated with body mass and body fat mass, whereas it was negatively correlated with energy intake and uncoupling protein 1 content in brown adipose tissue. Our results suggest that postweaning development in terms of body mass and thermogenesis is predominantly influenced by the postweaning photoperiod, while the preweaning photoperiod experience could chronically modify thermogenesis but not body mass. Furthermore, serum leptin,acting as a potential adipostatic signal, may be involved in the regulation of both energy intake and energy expenditure.

“…Syrian hamsters housed in groups for 65-75·days displayed a chronic 13% reduction in massspecific resting metabolic rate, accompanied by a 20% increase in body mass and a 53% increase in body fatness, relative to individuals housed individually (Borer et al, 1988). Decrease in maintenance metabolism has also been demonstrated in collared lemmings (Powell et al, 2002). In particular, male lemmings exposed to SD for 10·days had significantly lower total energy expenditure, resting energy expenditure and UCP-1 mRNA levels than animals maintained in LD, whereas nonresting energy expenditure (related to activity) was not affected by photoperiod.…”

Section: Discussionmentioning

confidence: 78%

Effect of photoperiod on body mass, food intake and body composition in the field vole,Microtus agrestis

Król

Redman

Thomson

et al. 2005

SUMMARY Many small mammals respond to seasonal changes in photoperiod by altering body mass and adiposity. These animals may provide valuable models for understanding the regulation of energy balance. Here, we present data on the field vole (Microtus agrestis) – a previously uncharacterised example of photoperiod-induced changes in body mass. We examined the effect of increased day length on body mass, food intake, apparent digestive efficiency,body composition, de novo lipogenesis and fatty acid composition of adipose tissue in cold-acclimated (8°C) male field voles by transferring them from a short (SD, 8 h:16 h L:D) to long day photoperiod (LD, 16 h:8 h L:D). During the first 4 weeks of exposure to LD, voles underwent a substantial increase in body mass, after which the average difference between body masses of LD and SD voles stabilized at 7.5 g. This 24.8% increase in body mass reflected significant increases in absolute amounts of all body components, including dry fat mass, dry lean mass and body water mass. After correcting body composition and organ morphology data for the differences in body mass, only gonads (testes and seminal vesicles) were enlarged due to photoperiod treatment. To meet energetic demands of deposition and maintenance of extra tissue, voles adjusted their food intake to an increasing body mass and improved their apparent digestive efficiency. Consequently, although mass-corrected food intake did not differ between the photoperiod groups, the LD voles undergoing body mass increase assimilated on average 8.4 kJ day-1 more than animals maintained in SD. The majority(73–77%) of the fat accumulated as adipose tissue had dietary origin. The rate of de novo lipogenesis and fatty acid composition of adipose tissue were not affected by photoperiod. The most important characteristics of the photoperiodic regulation of energy balance in the field vole are the clear delineation between phases where animals regulate body mass at two different levels and the rate at which animals are able to switch between different levels of energy homeostasis. Our data indicate that the field vole may provide an attractive novel animal model for investigation of the regulation of body mass and energy homeostasis at both organism and molecular levels.