Metabolic adaptation of mice in a cool environment

Kunitoshi Uchida, Tetsuya Shiuchi, Hitoshi Inada, Yasuhiko Minokoshi, Makoto Tominaga

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

Homeothermic animals, including humans, live by adapting to changes in ambient temperature. Numerous studies have demonstrated cold exposure (at approximately 5°C) improves glucose tolerance despite reducing insulin secretion and increasing energy expenditure. To determine the effects of a small reduction in ambient temperature on energy metabolism, we compared two groups of mice; one exposed to a cool environment (20°C) and the other maintained in a near-thermoneutral environment (25°C) for 10 days. Both glucose-induced insulin secretion and glucose response were significantly impaired in mice exposed to a cool environment. In the cool temperature-exposed mice, skin temperatures were reduced, and plasma norepinephrine levels were increased, suggesting that impairment of insulin secretion was facilitated by induction of sympathetic nervous activity due to skin cooling. In addition, expression of GLUT4 mRNA was increased significantly in inguinal subcutaneous adipose tissue (IWAT) but not in epididymal or brown adipose tissue or skeletal muscle in these mice. Moreover, expression of Dok1, a molecule linked to activation of insulin receptors in adipocyte hypertrophy, and Cd36, a molecule related to NEFA uptake, were also increased at mRNA and/or protein levels only in IWAT of the cool temperature-exposed mice. Fatty acid synthesis was also facilitated, and fat weights were increased only in IWAT from mice kept at 20°C. These results suggest that a small reduction in ambient temperature can affect glucose homeostasis through regulation of insulin secretion and preferentially enhances fat storage in IWAT. These adaptations can be interpreted as preparation for a further reduction in ambient temperature.

Original languageEnglish
Pages (from-to)765-774
Number of pages10
JournalPflugers Archiv European Journal of Physiology
Volume459
Issue number5
DOIs
Publication statusPublished - 2010 Apr
Externally publishedYes

Keywords

  • Cool environment
  • Fat storage
  • Glucose metabolism
  • Sympathetic nervous activity
  • White adipose tissue

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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