ANDROGEN AND GLUCOCORTICOID RECEPTOR HETERODIMER FORMATION - A POSSIBLE MECHANISM FOR MUTUAL INHIBITION OF TRANSCRIPTIONAL ACTIVITY

The androgen and glucocorticoid hormones elicit divergent and often op posing effects in cells, tissues, and animals, A wide range of physiol ogical and molecular biological evidence suggests that the receptors t hat mediate these effects, the androgen and glucocorticoid re ceptors (AR and GR, respectively), influence each other's transcriptional acti vity. We now show that coexpressed AR and GR indeed do interact at the transcriptional level and that this interaction is correlated with th eir ability to form heterodimers at a common DNA site, in vitro and in vivo. Furthermore, mutants that cannot heterodimerize do not inhibit each other's activity, These observations provide the first evidence t hat the opposing physiological effects of the androgen and glucocortic oid hormones are due to the direct physical interaction between their receptors at the transcriptional level.