Thyroid hormone receptors: The challenge of elucidating isotype-specific functions and cell-specific response

Thyroid hormone receptors TRα1, TRβ1 and TRβ2 are broadly expressed and exert a pleiotropic influence on many developmental and homeostatic processes. Extensive genetic studies in mice precisely defined their respective function. The purpose of the review is to discuss two puzzling issues: The isoform specificity problem: the different functions of TRα1, TRβ1 and TRβ2 might reflect either their different distribution in tissues or differences in...