Giordano A L, Ahdieh H B, Mayer A D, Siegel H I, Rosenblatt J S
Institute of Animal Behavior, Rutgers State University, Newark, New Jersey 07102.
Horm Behav. 1990 Jun;24(2):232-55. doi: 10.1016/0018-506x(90)90007-k.
In a previous study, high nuclear estrogen receptor concentrations in the preoptic area (POA) were found on Day 16 of pregnancy to prime females to respond to a subsequent low dose of estradiol benzoate (EB) after hysterectomy-ovariectomy by exhibiting maternal behavior in 48 hr. Receptor concentrations in the POA were found to be higher than those in the hypothalamus (HYP). The present study investigated when nuclear estrogen receptors increase during pregnancy in POA and when the difference in receptor concentrations between POA and HYP occurs. An attempt was made to reproduce these pregnancy changes with a 16-day treatment of estrogen and progesterone in ovariectomized (OVX), nulliparous rats. In Experiment 1, we measured cytosol and nuclear estrogen receptor concentrations in the POA and HYP of female rats during pregnancy. Nuclear receptor concentrations in the POA increased beginning on Day 10, increased again on Day 16, and continued at this high level for the remainder of pregnancy. Nuclear estrogen receptor concentrations in the HYP remained at a lower level throughout most of pregnancy until Day 22 when they increased significantly. In Experiment 2, we tested the maternal behavior and measured estrogen receptor concentrations in OVX, steroid-primed, nulliparous rats after hysterectomy (H) and EB treatment. While 90% of estradiol (E) + progesterone (P)-primed females displayed short-latency maternal behavior 48 hr after H and EB treatment, 46% of E + vehicle (V)-treated controls were maternal. At 0 hr (prior to H and EB treatment), there was a significantly larger nuclear receptor accumulation in the POA but significantly attenuated receptor binding in the HYP. P treatment significantly affected cytosol and nuclear estrogen receptor dynamics. Differences in nuclear estrogen receptor concentrations were shown to be based on the number of available binding sites and not to changes in receptor affinity for estradiol.
在之前的一项研究中，发现在妊娠第16天时，视前区（POA）的核雌激素受体浓度较高，这使雌性大鼠在子宫切除-卵巢切除术后对随后低剂量的苯甲酸雌二醇（EB）产生反应，在48小时内表现出母性行为。研究发现，POA中的受体浓度高于下丘脑（HYP）中的受体浓度。本研究调查了POA中核雌激素受体在妊娠期何时增加，以及POA和HYP之间受体浓度的差异何时出现。尝试通过对去卵巢（OVX）的未孕大鼠进行为期16天的雌激素和孕酮治疗来重现这些妊娠变化。在实验1中，我们测量了妊娠期间雌性大鼠POA和HYP中的胞质溶胶和核雌激素受体浓度。POA中的核受体浓度从第10天开始增加，在第16天再次增加，并在妊娠剩余时间内维持在这一高水平。HYP中的核雌激素受体浓度在整个妊娠的大部分时间里保持在较低水平，直到第22天显著增加。在实验2中，我们测试了子宫切除（H）和EB治疗后OVX、接受类固醇预处理的未孕大鼠的母性行为，并测量了雌激素受体浓度。虽然90%接受雌二醇（E）+孕酮（P）预处理的雌性大鼠在H和EB治疗后48小时表现出短潜伏期母性行为，但接受E+赋形剂（V）治疗的对照组中有46%表现出母性行为。在0小时（H和EB治疗前），POA中有明显更多的核受体积累，但HYP中的受体结合明显减弱。P处理显著影响胞质溶胶和核雌激素受体动力学。核雌激素受体浓度的差异显示是基于可用结合位点的数量，而不是受体对雌二醇亲和力的变化。
