Studies on mechanism of heat production in the house musk shrew (Suncus murinus) with unstable body temperature.

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 16500276
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Laboratory animal science
• Research Institution: Nagoya University
• Principal Investigator: ODA Sen-ichi Nagoya University, Graduate School of Bioagricultural Sciences, Professor, 大学院・生命農学研究科, 助教授 (60023660)
• Project Period (FY): 2004 – 2005
• Keywords: shrew (Suncus murinus) / brown adipose tissue / heat production / uncoupling protein-1 (Ucp-1) / deiodinase-2 (D2) / cold intolerance

Research Abstract

The house musk shrew (Suncus murinus), or suncus, is a unique experimental animal that is thought to be cold intolerant. When it is maintained in low temperature room, it becomes hypothermic, immobile, and eventually dies.
1) We found that the suncus are more susceptible to cold than mice, and that one reason for their cold intolerance is a malfunction of heat production and lipid depletion in brown adipose tissue (IBAT).
2) Neither mild cold exposure nor a high-fat diet alone induced up-regulation of the mRNAs for uncoupling protein 1 (Ucp1) and type II 5'-deiodinase (D2) in BAT. However, combinations of cold exposure and high-fat diet significantly increased both mRNAs. Therefore, cold intolerance in suncus may be partly caused by dietary components.
3) We did cDNA cloning of suncus Ucp1 and compared it to other species. The deduced amino acid sequence showed high homology with other mammalian UCP1. Northern blot analysis revealed mRNA in BAT as in other mammals. However, a difference in an amino acid residue was observed in an important residue for thermogenesis. Genomic sequence analysis showed that this difference existed in our two genetically distant laboratory colonies. These results suggest that the cold intolerance in suncus may be derived from low thermogenic activity of UCP1.

Research Products

• [Journal Article] Change in Ucp1 mRNA expression by long-term cold exposure under normal or high-fat diet feeding in a cold-intolerant mammal,suncus. (2006)
  • Author(s): Suzuki, D., Murata Y., Oda, S
  • Journal Title: Experimental Animals July(in press)
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Unique regulation of thyroid hormone metabolism during fasting in the house musk shrew (Suncus murinus,Insectivora : Soricidae) (2006)
  • Author(s): Takeuchi Y., Suzuki D., Oda S., Refetoff S., Seki K., Tunekawa K, Kasahara T., Murakami M., Murata Y
  • Journal Title: General and Comparative Endocrinology, 146 Pages: 236-241
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Change in Ucp1 mRNA expression by long-term cold exposure under normal or high-fat diet feeding in a cold-intolerant mammal, suncus. (2006)
  • Author(s): Suzuki, D., Murata Y., Oda, S.
  • Journal Title: Experimental Animals July(in press)
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Unique regulation of thyroid hormone metabolism during fasting in the house musk shrew (Suncus murinus, Insectivora : Soricidae). (2006)
  • Author(s): Takeuchi Y., Suzuki D., Oda S., Refetoff S., Seki K., Tunekawa K., Kasahara T., Murakami M., Murata Y.
  • Journal Title: General and Comparative Endocrinology 146 Pages: 236-241
  • Description: 「研究成果報告書概要(欧文)」より