Exploration of the role of serum factors in maintaining bone mass during hibernation in black bears

Bradford, Rachel Marie

doi:10.37099/mtu.dc.etds/286

Cited by 1 publication

(3 citation statements)

References 291 publications

(428 reference statements)

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“…In a separate study in little brown bats, NPY expression remained elevated throughout hibernation (Laemle and Cotter 1992). Increased NPY expression (mRNA) was also found in hibernating jerboas (Jaculus orientalis) (El Ouezzani et al 2001) and the serum of American black bears (Bradford 2010) in comparison to animals in summer. Of additional significance, NPY receptor Y1 may induce reduction of T b associated with torpor (Dark and Pelz 2008).…”

Section: Neuropeptide-ymentioning

confidence: 81%

“…This pattern occurs in concert with the accumulation of lipid in the fall until the intake of food ceases entirely and lipolysis begins. American black bears experience low adiponectin concentrations during hibernation (Bradford 2010). Low adiponectin levels are consistent with the requirement for conserving energy during hibernation; therefore, any protective function adiponectin may have on bone is likely second to the metabolic actions of this hormone.…”

Section: Adiponectinmentioning

confidence: 90%

“…In American black bears, PTH levels increased during hibernation and peaked in the post-hibernation season relative to pre-hibernation (Donahue et al 2006a). Increased PTH during hibernation and post-hibernation would be expected to signal the release of calcium from the bone matrix, but bone resorption decreases (McGee et al 2008;Bradford 2010) and serum calcium is unchanged (Floyd et al 1990;Bradford 2010). However, the PTH assay used in these studies detects large C-terminal PTH (C-PTH) fragments in addition to the full protein (PTH 1-84).…”

Section: Parathyroid Hormonementioning

confidence: 99%

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Endocrine Regulation of Bone and Energy Metabolism in Hibernating Mammals

Doherty

Florant

Donahue

2014

Integrative and Comparative Biology

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Precise coordination among organs is required to maintain homeostasis throughout hibernation. This is particularly true in balancing bone remodeling processes (bone formation and resorption) in hibernators experiencing nutritional deprivation and extreme physical inactivity, two factors normally leading to pronounced bone loss in non-hibernating mammals. In recent years, important relationships between bone, fat, reproductive, and brain tissues have come to light. These systems share interconnected regulatory mechanisms of energy metabolism that potentially protect the skeleton during hibernation. This review focuses on the endocrine and neuroendocrine regulation of bone/fat/energy metabolism in hibernators. Hibernators appear to have unique mechanisms that protect musculoskeletal tissues while catabolizing their abundant stores of fat. Furthermore, the bone remodeling processes that normally cause disuse-induced bone loss in non-hibernators are compared to bone remodeling processes in hibernators, and possible adaptations of the bone signaling pathways that protect the skeleton during hibernation are discussed. Understanding the biological mechanisms that allow hibernators to survive the prolonged disuse and fasting associated with extreme environmental challenges will provide critical information regarding the limit of convergence in mammalian systems and of skeletal plasticity, and may contribute valuable insight into the etiology and treatment of human diseases.

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