Effects of seasonality and fasting on the body mass and plasma growth hormone concentrations of the raccoon dog (Nyctereutes procyonoides) and the blue fox (Alopex lagopus)

Citation
Am. Mustonen et al., Effects of seasonality and fasting on the body mass and plasma growth hormone concentrations of the raccoon dog (Nyctereutes procyonoides) and the blue fox (Alopex lagopus), Z NATURFO C, 56(5-6), 2001, pp. 437-443
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES
ISSN journal
0939-5075 → ACNP
Volume
56
Issue
5-6
Year of publication
2001
Pages
437 - 443
Database
ISI
SICI code
0939-5075(200105/06)56:5-6<437:EOSAFO>2.0.ZU;2-0
Abstract
Growth hormone (GH) promotes growth and endochondral ossification, but it i s also important in the response to fasting due to its effects of increasin g gluconeogenesis and lipolysis. In this study eleven raccoon dogs and blue foxes were followed for six months and their body mass and GH levels were measured. In November half of the animals of both species were put to a thr ee-week fast. There were no significant differences in the GH levels betwee n the animals of different ages and the subadults and adults both had quite low GH levels in the summer. Fasting had no effect on the GH levels of the raccoon dogs, but the fasting blue foxes had lower GH concentrations than the controls in Nov 16(th) The control blue foxes experienced a significant increase in the GH levels in early November acid the fasting blue foxes in late November. The GH concentrations of all the raccoon dogs rose in early December. As fasting did not cause an elevation in the GH levels but the c oncentrations increased with decreasing temperature and shortening daylengt h, the autumnal GH secretion of these species could be regulated by endogen ous seasonal rhythms entrained by exogenous Zeitgebers such as temperature or photoperiod. The autumnal increase of GH levels contributes to the respo nse to fasting as an adaptation to survive the winter months with inadequat e nutrition. The raccoon dog which spends the coldest part of the winter in winter sleep seems to be better adapted to a total fast than the actively wintering blue fox.