Table 2.

Summary of two neuroendocrine factors influencing bone and fat metabolism in hibernators^a

Hormone	Species	Seasonal concentrations						References
		Fall (pre-hibernation)	Winter (hibernation)			Spring (post-hibernation)	Summer (active)
			Early hibernation	Late hibernation
NPY	American Black Bear (U. americanus)	211.9 pmol/l	226.17 pmol/l			192.49 pmol/l		Bradford et al. (2010)
	Daurian Ground squirrel (S. dauricus)	0.70RUb	0.75RU			1.0RU	0.56RU	Xing et al. (2012)
	Greater Egyptian Jerboa (J. orientalis)		23.9RU				10.4RU	El Ouezzani et al. (2001)
	Greater Mouse-tailed Bat (R. microphyllum)	2.8 pg/mgb				1.25 pg/mg	3.5 pg/mg	Levin et al. (2012)
Serotonin	American Black Bear	753.1 ng/ml	600.95 ng/ml			689.55 ng/ml		Bradford et al. (2010)
	Woodchuck (M. monax)	5.0 ng/mgc	5.1 ng/mg			5.3 ng/mg		Young et al. (1979)
	Marmot (M. flaviventris)		10.4 nM				1.1 nM	Reid et al. (1992)
	Golden-mantled Ground Squirrel (C. lateralis)		0.30–0.40 µg/g				0.40–0.70 µg/g	Spafford and Pengelley (1971)
	Little Brown Bat (M. lucifugus)	4.15 µg/gc	11.44 µg/g	4.94 µg/g		4.05 µg/g		Haymovits et al. (1976)

^aThis table reflects a summary of key studies in hibernation with potential insight into bone metabolism. The table is not intended to be all inclusive and the ranges given do not highlight seasonal changes that may be found in particular studies.

^bDenotes RNA gene expression.

^cProtein expression of serum adiponectin.