Studies on the non-activated and activated forms of the estrogen receptor.

The activation of the steroid receptor is a necessary process for the biological role of the receptor. Many factors are involved in this mechanism; in addition to time, temperature, and salt concentration, RNA and RNAase can also affect the transformation of the non-activated to the activated form of the receptor. Using as a model the estrogen receptor of fetal uterus of guinea-pig, the studies of the interaction with three different monoclonal antibodies (D547, H222 and H226) reveal structural transformation during the process of the receptor activation. These conformational transformations suggest that a change in the exposure of the functional domains of the estrogen receptor occurs during activation.