Differential sensitivity of estrogen target tissues: the role of the receptor.

Abstract

In this report, we describe the neuroendocrine features of the estrogen-implanted ovariectomized rat and define a number of estrogen-induced responses in these animals. We further demonstrate differential sensitivity to estradiol among several estrogen target tissues and investigate the role of the estrogen receptor in the mediation of this phenomenon. Ovariectomized rats implanted with a range of estradiol doses (1 μ-5 mg estradiol/capsule) provided a good experimental model for generation of dose response curves. These animals have serum estradiol levels that span the physiological range and that modulate numerous neuroendocrine endpoints. Using this animal model, dose response curves between estradiol and six estrogeninduced responses were generated. These responses included uterine wet and dry weight, negative and positive feedback of estrogen on serum LH levels, the LHRH content of neurosecretory terminals of the medial basal hypothalamus, and the size of the LHRH bolus released from the median emine...