Altered expression of SOCS3 in the hypothalamic arcuate nucleus during seasonal body mass changes in the field vole, Microtus agrestis.

Abstract

We have previously shown that cold-acclimated (8 degrees C) male field voles (Microtus agrestis) transferred from short day (SD, 8 h light) to long day (LD, 16 h light) photoperiod exhibit an increase in body mass lasting 4 weeks, after which they stabilise at a new plateau approximately 7.5 g (24.8%) higher than animals maintained in SD. By infusing voles with exogenous leptin, we have also demonstrated that SD voles respond to the hormone by reducing body mass and food intake, whereas LD animals increasing body mass are resistant to leptin treatment. In the present study, we investigated whether seasonal changes in body mass could be linked to modulation of the leptin signal by suppressor of cytokine signalling-3 (SOCS3). We used in situ hybridisation to examine hypothalamic arcuate nucleus (ARC) expression of SOCS3, neuropeptide Y (NPY), agouti-related peptide (AgRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) genes in 90 voles exposed to either SD or LD for up to 11 weeks. LD voles increasing body mass had significantly higher levels of SOCS3 mRNA than SD or LD voles with a stable body mass. There were no associated changes in expression of NPY, AgRP, POMC and CART genes. These results suggest that voles that regulate body mass at either the lower (SD) or upper (LD) plateau remain sensitive to leptin action, whereas SOCS3-mediated leptin resistance is a short-term mechanism that enables animals to move between the stable body mass plateaus. Our data provide evidence that expression of SOCS3 in the ARC is involved in the modulation of the strength of the leptin signal to facilitate seasonal cycles in body mass and adiposity.

• Authors: E Król, A Tups, Z A Archer, A W Ross, K M Moar, L M Bell, J S Duncan, C Mayer, P J Morgan, J G Mercer, J R Speakman
• Journal: Journal of neuroendocrinology (J Neuroendocrinol) Vol. 19 Issue 2 Pg. 83-94 (Feb 2007) ISSN: 0953-8194 [Print] United States
• PMID: 17214870 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Agouti-Related Protein
• Intercellular Signaling Peptides and Proteins
• Leptin
• Nerve Tissue Proteins
• Neuropeptide Y
• RNA, Messenger
• Suppressor of Cytokine Signaling Proteins
• cocaine- and amphetamine-regulated transcript protein
• Pro-Opiomelanocortin

Topics

• Acclimatization (physiology)
• Agouti-Related Protein
• Animals
• Arcuate Nucleus of Hypothalamus (metabolism)
• Arvicolinae (metabolism)
• Body Weight (physiology)
• Gene Expression Regulation (physiology)
• Intercellular Signaling Peptides and Proteins (genetics, metabolism)
• Leptin (physiology)
• Male
• Nerve Tissue Proteins (genetics, metabolism)
• Neuropeptide Y (genetics, metabolism)
• Photoperiod
• Pro-Opiomelanocortin (genetics, metabolism)
• RNA, Messenger (analysis)
• Seasons
• Signal Transduction (physiology)
• Suppressor of Cytokine Signaling Proteins (genetics, metabolism)