Insulin-like growth factor-binding proteins and bone metabolism.

Insulin-like growth factor-binding proteins (IGFBPs) are important regulators of bone metabolism. However, their precise roles are not fully understood, since IGFBPs can have both enhancing and inhibiting effects on IGF action, depending on context and posttranslational modifications, as well as IGF-independent effects. This review focuses on recent findings from cell culture, rodent models, and clinical studies concerning local IGFBP-2, IGFBP-4, and IGFBP-5 action in bone.