Selective agonists and antagonists to thyroid hormone action.

Selective thyromimetics have been designed and shown to exhibit some of the beneficial effects of thyroid hormones, such as lowering of cholesterol and weight reduction, without the adverse thyroid hormone action on muscle, bone, and heart rate. Progress has also been made in attempting to treat hyperthyroidism by synthesizing antagonists that block thyroid hormone action, at the level of the thyroid hormone receptor or of the thyrotropin receptor. Clinical trials are still awaited, however, to verify whether these potentially promising agents will indeed prove to be of clinical therapeutic value.