Metabolic adaptations of overwintering European common lizards (Lacerta vivipara)

Citation
Y. Voituron et al., Metabolic adaptations of overwintering European common lizards (Lacerta vivipara), PHYSIOL B Z, 73(3), 2000, pp. 264-270
Citations number
37
Categorie Soggetti
Animal Sciences",Physiology
Journal title
PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY
ISSN journal
15222152 → ACNP
Volume
73
Issue
3
Year of publication
2000
Pages
264 - 270
Database
ISI
SICI code
1522-2152(200005/06)73:3<264:MAOOEC>2.0.ZU;2-H
Abstract
The European common lizard Lacerta vivipara, a reptile of cold-temperate cl imates, provides us an interesting model of low-temperature adaptation. Ind eed its unique cold-hardiness strategy, which employs both freeze tolerance and freeze avoidance, may be seen as the primary reason for its large dist ribution, which extends from Spain to beyond the Arctic circle. To study th e metabolism supporting this capacity, we used three techniques: two techni ques of calorimetry (oxygen consumption and thermogenesis) and nuclear magn etic resonance spectroscopy. These techniques were used to examine the meta bolic balance and the different molecular pathways used between three diffe rent periods through the year (September, January, and May). The results sh ow a significant 20% augmentation of winter anaerobic metabolism compared t o other periods of the year. This is mainly because of an activation of the lactic fermentation pathway leading to an increase of lactate concentratio n (>34% in winter). Furthermore, glucose, which increases some 245% in wint er, is used as antifreeze and metabolic substrate. Furthermore, this study provides evidence that the physiological adaptations of the common lizard d iffer from those of other ectotherms such as Rana sylvatica. Concentrations of alanine and glycerol, commonly used as antifreeze by many overwintering ectotherms, do not increase during winter.