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

Peacock, W L; Król, Elżbieta; Moar, Kim-Marie; McLaren, James; Mercer, Julian G.; Speakman, John R.

doi:10.1242/jeb.00719

Cited by 39 publications

(31 citation statements)

References 60 publications

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“…However, in spite of substantial increases in SOCS3 gene expression in the ARC of voles exposed to LD, we found no significant changes in the hypothalamic expression of mRNA for NPY, AgRP, POMC and CART genes. Changes in NPY, AgRP, POMC and CART were also not detected in our previous studies, where bank voles (Clethrionomys glareolus) were exposed to SD or LD for 12 weeks (Peacock et al 2004). However, these changes in the first-order neuropeptides believed to control food intake were perhaps not surprising because we have also shown that exposure to LD did not significantly affect food intake, once differences in body mass were accounted for (Peacock et al 2004, Król et al 2005.…”

Section: Discussionsupporting

confidence: 53%

“…Changes in NPY, AgRP, POMC and CART were also not detected in our previous studies, where bank voles (Clethrionomys glareolus) were exposed to SD or LD for 12 weeks (Peacock et al 2004). However, these changes in the first-order neuropeptides believed to control food intake were perhaps not surprising because we have also shown that exposure to LD did not significantly affect food intake, once differences in body mass were accounted for (Peacock et al 2004, Król et al 2005. Rather, the increase in mass and adiposity was mediated primarily by an increase in digestive efficiency.…”

Section: Discussioncontrasting

confidence: 43%

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Regulation of body mass and adiposity in the field vole, Microtus agrestis: a model of leptin resistance

Król¹,

Speakman²

2007

Journal of Endocrinology

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Adult mammals are typically highly resistant to perturbations in their energy balance. In obese humans, however, this control appears to be lost. Apart from a few exceptional cases, this loss of control occurs despite appropriate levels of circulating leptin -suggesting that elevated adiposity may be a consequence of failure to respond to the leptin signal: leptin resistance. When cold-acclimated male field voles (Microtus agrestis) are transferred from short (SD, 8 h light) to long (LD, 16 h light) photoperiods, they increase dramatically in body mass and fatness for about 4 weeks. After this period, their mass stabilizes at a new plateau about 25% higher than animals maintained in SD. The increase in adiposity is not caused by significant increases in food intake, but reflects an increase in digestive efficiency. Measures of circulating leptin reveal that the increased adiposity is matched by increased circulating leptin. By infusing voles with exogenous leptin, we have demonstrated that SD voles are leptin sensitive (reducing both body mass and food intake), whereas LD animals are leptin resistant. Voles may therefore be a useful model for understanding the process of leptin resistance. The change in leptin sensitivity in voles was not associated with changes in the levels of gene expression of the orexogenic or anorexogenic neuropeptides, such as neuropeptide Y, agouti-related peptide, POMC and cocaine-and amphetamine-regulated transcript, measured in the hypothalamic arcuate nucleus (ARC). During the phase that body mass was increasing, however, there was a transient increase in the ARC expression of suppressor of cytokine signalling-3 (SOCS3). These data suggest that the changes in the expression of SOCS3 in the ARC may be involved in leptin resistance. However, the mechanism by which these changes may be linked to alterations in digestive efficiency that underpin the changes in adiposity, or how the differences are signalled by changes in photoperiod, remains unclear.

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Section: Discussionsupporting

confidence: 53%

Section: Discussioncontrasting

confidence: 43%

Regulation of body mass and adiposity in the field vole, Microtus agrestis: a model of leptin resistance

Król¹,

Speakman²

2007

Journal of Endocrinology

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“…Similar seasonal changes (i.e. SD-induced decreases in body mass and adiposity) have also been demonstrated in the European hamster (Cricetus cricetus; Canguilhem et al, 1988), montane vole (Microtus montanus; Petterborg, 1978), meadow vole (Microtus pennsylvanicus; Dark and Zucker, 1984), tundra vole (Microtus oeconomus; Wang and Wang, 1996) and bank vole (Clethrionomys glareolus; Peacock et al, 2004).…”

Section: Introductionsupporting

confidence: 63%

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

Król

Redman

Thomson

et al. 2005

Journal of Experimental Biology

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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.

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“…However, SD had no effect on energy intake in collared lemmings , bank voles (Clethrionomys glareolus) (Peacock et al, 2004) or field voles (Microtus agrestis) after correcting for differences in body mass (Król et al, 2005). In the present study, changing the direction of the photoperiod caused differences in digestible energy intake when juveniles had grown up.…”

Section: The Underlying Mechanism Of Body Mass Regulationcontrasting

confidence: 57%

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

Zhong

Wang

2007

Journal of Experimental Biology

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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.

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

Cited by 39 publications

References 60 publications

Regulation of body mass and adiposity in the field vole, Microtus agrestis: a model of leptin resistance

Regulation of body mass and adiposity in the field vole, Microtus agrestis: a model of leptin resistance

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

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

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