Journal of Comparative Physiology B

, Volume 163, Issue 7, pp 546–555

Metabolism, thermogenesis and daily rhythm of body temperature in the wood lemming, Myopus schisticolor

Authors

  • S. Saarela
    • Department of ZoologyUniversity of Oulu
  • R. Hissa
    • Department of ZoologyUniversity of Oulu
Article

DOI: 10.1007/BF00302113

Cite this article as:
Saarela, S. & Hissa, R. J Comp Physiol B (1993) 163: 546. doi:10.1007/BF00302113

Abstract

Wood lemmings (Myopus schisticolor) were captured during their autumnal migration in September and October. The animals were maintained at 12°C and under 12L:12D photoperiod. Basal metabolic rate and thermogenic capacity of the wood lemming were studied. Basal metabolic rate was 3.54 ml O2·g-1·h-1, which is 215–238% of the expected value. The high basal metabolic rate seems to be typical of rodents living in high latitudes. The body temperature of the wood lemming was high (38.0–38.8°C), and did not fluctuate much during the 24-h recording. The high basal metabolic rate and the high body temperature are discussed with regard to behavioural adaptation to a low-quality winter diet. Thermogenic capacity, thermal insulation and non-shivering thermogenesis of the wood lemming displayed higher values than expected: 53.0 mW·g-1, 0.53 mW·g-1·C-1 and 53.2 mW·g-1, respectively. Brown adipose tissue showed typical thermogenic properties, although its respiratory property was fairly low, but mitochondrial protein content was high compared to other small mammals. The 24-h recording of body temperature and motor activity did not reveal whether the wood lemming is a nocturnal animal. Possibly, the expression of a circadian rhythm was masked by peculiar feeding behaviour. It is concluded that the wood lemming is well adapted to living in cold-temperature climates.

Key words

MetabolismThermogenesisBrown adipose tissueCircadian rhythmWood lemming, Myopus

Abbreviations

BAT

brown adipose tissue; bm, body mass

BMR

basal metabolic rate

C

conductance

Cox

cytochrome-c-oxidase

HP

heat production

HPmax

maximum heat production

M

metabolism

NA

noradrenaline

NST

non-shivering thermogenesis

NSTmax

maximum non-shivering thermogenesis

RMR

resting metabolic rate

RQ

respiratory quotient

Ta

anibient temperature

Tb

body temperature

Tlc

lower critical temperature

UCP

uncoupling protein

vO2

oxygen consumption

vO2 max

maximum oxygen consumption

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Copyright information

© Springer-Verlag 1993