Influence of thyroid hormones on the GH-IGF-I axis.

There is a complex relationship between thyroid hormones, GH, and the insulin-like growth factors (IGFs). Thyroid hormones act at many sites from the hypothalamic control of GH release to the tissue expression of IGF-I and its binding proteins (IGFBPs). In this review, we present current knowledge of the effects of altered thyroid status on the GH-IGF-I axis, concentrating on the changes seen in IGF-I gene expression and circulating levels of GH and IGFBPs.