Steroid hormone receptors are members of the nuclear receptor family of ligand-activated transcriptional regulatory proteins. Recent work in the field of nuclear receptor action has demonstrated an association of receptors with coregulatory proteins termed “coactivators” and “corepressors.” In the absence of hormone, or in the presence of hormonal antagonists, nuclear receptors can repress transcription through their association with corepressors. Upon binding hormonal agonists, receptors bind target sites in DNA and recruit transcriptional coactivators. In turn, coactivators, functionally, and perhaps physically, bridge DNA-bound receptors and the general transcription machinery, forming a complex capable of promoting the activation of gene expression (1 -3 )
