ANALYSIS OF STEROID-RECEPTOR DOMAINS WITH THE AID OF ANTIHORMONES

1. The receptors for steroid hormones consist of well defined domains with overlapping functions. 2. Contrary to the classical view, it is n ow becoming increasingly evident that agonist binding regions of the l igand binding domain are not identical to those that bind steroid anta gonists. 3. The DNA binding domain can be activated equally well in pr esence of both agonists and antagonists, again contradicting the class ical view where only the physiologically active hormone was believed t o induce such a change. 4. In some cases, a synthetic antagonist is a more specific ligand for the receptor than the natural hormone. 5. Syn thetic antagonists are therefore important not only to alleviate disea se in the human subject, they have also become an important tool to el ucidate the mechanism of transactivation by steroid hormones.