[Thyroid hormone and skeletal metabolism].

The role of the hypothalamic-pituitary-thyroid axis is important in normal skeletal development, gain of bone mass, and regulation of adult bone metabolism. Hypothyroidism in childhood causes delayed bone maturation and growth disturbance and thyroid dysfunction in adult induces altered bone remodeling and an increased risk of bone fracture. Thyroid hormone actions in skeletal cells are mainly mediated by thyroid hormone receptor α (TRα) . The responses to thyroid hormone are regulated by type 2 and 3 iodothyronine deiodinase (DIO2 and DIO3) , which convert prohormone (T4) to active hormone (T3) . Euthyroid status is necessary for the homeostasis of human bone metabolism.