Altered estrogen action in the senescent rat uterus: a model for steroid resistance during aging

The estrogen stimulated rat uterus serves as a useful model to examine steroid resistance during aging. This system exhibits receptor loss, impaired stimulation of RNA polymerase II and defects in nuclear translocation (or enhanced association) of receptor-estradiol complexes. All of these defects appear to contribute in part to decreased estrogen responsiveness of the senescent rodent uterus.