Endocrine response to fasting in the overwintering captive raccoon dog (Nyctereutes procyonoides).
The raccoon dog (Nyctereutes procyonoides) is an omnivorous canid utilizing the passive wintering strategy in the boreal climate. Farmed raccoon dogs (n=12) were randomly assigned into two study groups on 26 November 2003. Between 3 December 2003 and 27 January 2004, half of the animals were fasted for 8 weeks and plasma weight-regulatory hormone concentrations determined on 26 November and 30 December 2003 and on 27 January 2004. The plasma peptide YY, ghrelin, and growth hormone (GH) concentrations increased due to food deprivation, while the T4 and Acrp30 concentrations decreased. Furthermore, the plasma GH concentrations were higher in the fasted raccoon dogs than in the fed animals, which had higher plasma insulin, glucagon, and T4 concentrations. However, fasting had no effect on the plasma leptin concentrations. The results confirm previous findings with unchanged leptin levels in fasting carnivores. Increased GH levels probably contribute to increased lipolysis and mobilization of fat stores. Ghrelin can also enhance lipolysis by increasing the GH levels. The decreased levels of T4 may reduce the metabolic rate. The plasma dopamine concentrations decreased due to fasting unlike observed previously in rats. Together with the unaffected adrenaline, noradrenaline, and cortisol concentrations, this suggests that food deprivation in winter does not cause stress to the raccoon dog but is an integral part of its natural life history.
Nieminen
Petteri
P
Department of Biology, University of Joensuu, FIN-80101, Joensuu, Finland.
Saarela
Seppo
S
Pyykönen
Teija
T
Asikainen
Juha
J
Mononen
Jaakko
J
Mustonen
Anne-Mari
AM
D000222:Adaptation, Physiological; D052242:Adiponectin; D000273:Adipose Tissue / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000502:physiology; D002395:Catecholamines / Q000097:blood; D004298:Dopamine / Q000097:blood*; D005215:Fasting / Q000097:blood*; D005260:Female; D054439:Ghrelin; D005934:Glucagon / Q000097:blood; D013006:Growth Hormone / Q000097:blood; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood; D020738:Leptin / Q000097:blood*; D036361:Peptide Hormones / Q000097:blood; D019894:Peptide YY / Q000097:blood*; D046031:Raccoon Dogs / Q000097:blood*; D011897:Random Allocation; D012621:Seasons; D013974:Thyroxine / Q000097:blood
D052242:Adiponectin; D002395:Catecholamines; D054439:Ghrelin; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D020738:Leptin; D036361:Peptide Hormones; D019894:Peptide YY; D013006:Growth Hormone; D005934:Glucagon; D013974:Thyroxine; D004298:Dopamine; D006854:Hydrocortisone