Supplementary Material for: Activation of the GPR30 Receptor Promotes Lordosis in Female Mice

<b><i>Background/Aims:</i></b> Estrogens are important effectors of reproduction and are critical for upregulating female reproductive behavior or lordosis in females. In addition to the importance of transcriptional regulation of genes by 17β-estradiol-bound estrogen receptors (ER), extranuclear signal transduction cascades such as protein kinase A (PKA) are also important in regulating female sexual receptivity. GPR30 (G-protein coupled receptor 30), also known as GPER1, a putative membrane ER (mER), is a G protein-coupled receptor that binds 17β-estradiol with an affinity that is similar to that possessed by the classical nuclear ER and activates both PKA and extracellular-regulated kinase signaling pathways. The high expression of GPR30 in the ventromedial hypothalamus, a region important for lordosis behavior as well as kinase cascades activated by this receptor, led us to hypothesize that GPR30 may regulate lordosis behavior in female rodents. <b><i>Method:</i></b> In this study, we investigated the ability of G-1, a selective agonist of GPR30, to regulate lordosis in the female mouse by administering this agent prior to progesterone in an estradiol-progesterone priming paradigm prior to testing with stud males. <b><i>Results:</i></b> As expected, 17β-estradiol benzoate (EB), but not sesame oil, increased lordosis behavior in female mice. G-1 also increased lordosis behavior in female mice and decreased the number of rejective responses towards male mice, similar to the effect of EB. The selective GPR30 antagonist G-15 blocked these effects. <b><i>Conclusion:</i></b> This study demonstrates that activation of the mER GPR30 stimulates social behavior in a rodent model in a manner similar to EB.

<b><i>背景与研究目的：</i></b> 雌激素是生殖过程的关键效应因子，对雌性生殖行为及脊柱前凸反射（lordosis）的上调调控至关重要。除17β-雌二醇结合雌激素受体（ER）介导的基因转录调控作用外，蛋白激酶A（PKA）等核外信号转导级联反应在调控雌性性接受性过程中同样发挥重要作用。GPR30（G蛋白偶联受体30，又称GPER1）是一种假定的膜型雌激素受体（mER），属于G蛋白偶联受体，可与17β-雌二醇结合，其结合亲和力与经典核雌激素受体相当，且能同时激活PKA与细胞外调节蛋白激酶（extracellular-regulated kinase）信号通路。GPR30在下丘脑腹内侧核——该区域不仅与脊柱前凸反射密切相关，同时也是该受体激活激酶级联反应的作用位点——中高表达，这一特征促使我们提出假设：GPR30可调控雌性啮齿类动物的脊柱前凸反射行为。
<b><i>研究方法：</i></b> 本研究采用雌二醇-孕酮预处理范式，在与种公鼠开展行为测试前，向雌性小鼠注射GPR30选择性激动剂G-1，以此探究其对雌性小鼠脊柱前凸反射行为的调控作用。
<b><i>研究结果：</i></b> 如预期所示，苯甲酸17β-雌二醇（EB）可增强雌性小鼠的脊柱前凸反射行为，而芝麻油对照组则无此效应；G-1同样可提升雌性小鼠的脊柱前凸反射水平，并减少其对雄性小鼠的排斥反应，其作用效果与EB高度相似。GPR30选择性拮抗剂G-15可阻断上述所有效应。
<b><i>研究结论：</i></b> 本研究证实，膜型雌激素受体GPR30的激活可通过与苯甲酸17β-雌二醇（EB）相似的调控途径，刺激啮齿类动物模型的相关社交行为。