Magnus Pfahl (La Jolla Cancer Research Foundation, Calif.): "Thyroid hormones as well as the vitamin A-derived hormones (retinoids) influence a myriad of biological processes, including such complex programs as metamorphosis and morphogenesis. Retinoids have also drawn particular attention in recent years because of their effectiveness against a number of skin diseases (including wrinkles) and their potential as anti- cancer and cancer-preventive agents. However, use of retinoids and thyroid hormones as therapeutics has been hampered by undesirable side effects-- which, for instance, in the case of retinoids range all the way from slight skin irritations to malformation in fetuses. Because of the manifold roles of both thyroid and retinoid hormones, and their potential as therapeutics, their mechanism of action has been of particular interest.
"A major advance toward understanding this was achieved by the cloning of specific nuclear receptors. The receptors turned out to belong to a large family of transcription ...
