Effects of seasonality and fasting on the plasma leptin and thyroxin levels of the raccoon dog (Nyctereutes procyonoides) and the blue fox (Alopex lagopus)

Citation
P. Nieminen et al., Effects of seasonality and fasting on the plasma leptin and thyroxin levels of the raccoon dog (Nyctereutes procyonoides) and the blue fox (Alopex lagopus), J EXP ZOOL, 289(2), 2001, pp. 109-118
Citations number
43
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences","Animal & Plant Sciences
Journal title
JOURNAL OF EXPERIMENTAL ZOOLOGY
ISSN journal
0022-104X → ACNP
Volume
289
Issue
2
Year of publication
2001
Pages
109 - 118
Database
ISI
SICI code
0022-104X(20010201)289:2<109:EOSAFO>2.0.ZU;2-0
Abstract
Plasma leptin and thyroxin concentrations of eleven raccoon dogs and eleven blue foxes were monitored for 6 months. Half of the animals were placed on a 3-week fast in November. Leptin levels were low in summer, but in Octobe r they rose significantly. In November, leptin concentrations decreased rap idly within a week although the body mass of the animals remained stable. T here were no significant differences between experimental groups for raccoo n dogs, but in blue foxes the fasting group had lower leptin levels than th e control group. High thyroxin levels in summer decreased as autumn progres sed, but thyroxin concentrations of the fasting groups increased at the end of the fast. Leptin levels of the raccoon dog and the blue fox are not det ermined only by the fat reserves of the animals, but they seem to reflect t he autumnal deposition of fat at the onset of winter. Blue foxes have metab olic rates of active animals during the winter and higher leptin levels in December than raccoon dogs. The superficially hibernating raccoon dogs have low leptin levels after the onset of winter perhaps as an adaptation to fa sting. J. Exp. Zool. 289:109-118, 2001. (C) 2001 Wiley-Liss, Inc.