(13,14,18,21). Apart from hormone binding, the carboxy-terminal domains of the different receptors have other functions. They are required for dimerization of the estrogen receptor (26), for hormone-dependent nuclear translocation (34), and for transcriptional inhibition by the glucocorticoid receptor (32). Furthermore, the carboxy-terminal regions in the estrogen, progesterone, and glucocorticoid receptors contain part of the trans-activation functions of these receptors (5,11,20,40