Fig. 2.

Some of the factors that influence osteoclastogenesis, osteoclast activity, and bone resorption in non-hibernators (A) compared to hibernators (B). InsR, insulin receptor; C-PTHr, C-PTH fragment receptor; GCr, glucocorticoid receptor; ucOC, uncarboxylated osteocalcin. Dashed lines represent reduced effects on bone in each pathway due to lowered bioactivity (e.g., adiponectin), impaired function (e.g., hyperinsulinemia, hyperleptinemia), or unbalanced processes (e.g., bone formation in non-hibernators during periods of high bone resorption). Arrows: activation; blunted arrows: blocked action; circled dash: impaired function; ?: mechanism still unknown; X: cell death.