Sá Susana I, Fonseca Bruno M
Department of BiomedicineUnit of Anatomy, Faculty of Medicine, University of Porto, Porto, Portugal
Faculty of MedicineCenter for Health Technology and Services Research (CINTESIS), University of Porto, Porto, Portugal.
J Endocrinol. 2017 May;233(2):197-207. doi: 10.1530/JOE-16-0663. Epub 2017 Mar 10.
Cyclic fluctuations of estradiol and progesterone in females influence neuronal activity in the ventrolateral division of the ventromedial hypothalamic nucleus (VMNvl), through the activation of progesterone receptors (PRs) and estrogen receptors (ERs). The expression of ER and PR in the VMNvl is influenced by their cognate ligands and is a central upstream trigger in the pathway of VMNvl-dependent modulation of endocrine responses. By studying the role played by estradiol and progesterone in PR and ERa expression in the VMNvl along the estrous cycle and how the two receptors interact in the same neuron, we aim to evaluate the synergistic action of both ovarian hormones in the regulation of VMNvl activity. In animals at all phases of the estrous cycle, the number of VMN neurons expressing PR or ERa was estimated by stereological methods, and the percentage, and rostro-caudal distribution, of neurons simultaneously expressing both receptors was determined. The highest number of PR-immunoreactive neurons was seen at proestrus, and of ERa-immunoreactive neurons was seen at proestrus and metestrus. The ERa/PR co-localization is increased at caudal levels. Approximately half the neurons expressing PR co-express ERa, a proportion that stays constant along the estrous cycle. The percentage of ERa neurons co-expressing PR changes from 60% at proestrus to 40% at metestrus. Fluctuations in circulating ovarian hormone levels promote coordinated changes in PR and ERa expression and co-localization. This may be an important mechanism in the regulation of input relayed by the VMNvl, allowing a precise modulation of endocrine responses.
雌性动物体内雌二醇和孕酮的周期性波动，通过激活孕酮受体（PRs）和雌激素受体（ERs），影响腹内侧下丘脑核腹外侧部（VMNvl）的神经元活动。VMNvl中ER和PR的表达受其同源配体的影响，是VMNvl依赖性内分泌反应调节通路中的一个核心上游触发因素。通过研究雌二醇和孕酮在发情周期中对VMNvl中PR和ERα表达的作用，以及这两种受体在同一神经元中的相互作用，我们旨在评估这两种卵巢激素在调节VMNvl活性中的协同作用。采用体视学方法估计发情周期各阶段动物VMN中表达PR或ERα的神经元数量，并确定同时表达这两种受体的神经元的百分比及其在 rostro-caudal 方向的分布。在发情前期可见PR免疫反应性神经元数量最多，在发情前期和发情后期可见ERα免疫反应性神经元数量最多。ERα/PR共定位在尾部水平增加。大约一半表达PR的神经元同时共表达ERα，这一比例在发情周期中保持恒定。共表达PR的ERα神经元百分比从发情前期的60%变化到发情后期的40%。循环卵巢激素水平的波动促进PR和ERα表达及共定位的协调变化。这可能是调节VMNvl传递的输入的一个重要机制，从而实现对内分泌反应的精确调节。
