Estrogen receptor 2 (ESR2) is involved in oestrogen-related apoptosis in cell cycle spermatogenesis but their effects have not yet confirmed in pig. Therefore, this study was performed to investigatetheir association with semen motility and kinematic characteristics. DNA samples from 126 Duroc pigs with records of sperm motility and kinematic characteristics [Total motile spermatozoa (MOT), Curvilinear velocity(VCL), Straight-line velocity(VSL), the ratio between VSL and VCL(LIN), Amplitude of Lateral Head displacement(ALH)] were used in present study. A single nucleotide polymorphism (g.35547A>G) was associated with MOT, VCL, VAP and ALH in Duroc population (p < 0.05). Therefore, we suggest that the porcine ESR2 may be used as a molecular marker for Duroc boar semen quality, although its functional effect was not clear yet. These results will improve the understanding of the functions of the ESR2 in spermatogenesis within the reproductive tracts, and will shed light on ESR2 as a candidate gene in the selection of good sperm quality boars.

Estrogen is a primary steroid hormone to govern cell fates in the endometrium. It induces expression of a spectrum of genes such as early growth response 1 (Egr1) critical for dynamic change of uterine environments for embryo implantation. Egr1 belongs to the Egr family of zinc finger transcription factors consisting of 4 members (Egr1 to Egr4) that are co-expressed in many different tissues, suggesting that they may have some redundant functions. Bisphenol A (BPA) is a well-known endocrine disruptor with potent estrogenic activity on reproductive system. Here we have demonstrated molecular pathway(s) by which estrogen (17β estradiol, E2) and BPA regulates Egr1 in uterus. Eight-week-old female mice were ovariectomized (OVX) and rested for a week. Uteri of OVX mice treated with E2, BPA and/or progesterone (P4) were collected 2 h after hormone treatment unless otherwise indicated. ICI 182,780 [estrogen receptor (ER) antagonist] and RU486 [progesterone receptor (PR) antagonist] were pretreated 30 min before hormone treatment. Collected uteri were mainly utilized for RT-PCR, realtime-RT-PCR and Western blotting. Egr1 mRNA was rapidly induced with the highest level at 2h after E2 treatment and gradually decreased to basal levels at 12 h. Pretreatment of ICI 182,780 effectively inhibited E2-induced phosphorylation of ERK1/2 and AKT as well as Egr1 transcription. U0126 (a pharmacological ERK1/2 inhibitor), but not Watmannin (a AKT inhibitor), significantly blocked E2-induced Egr1 expression as well as ERK1/2 phosphorylation in the uterus. P4 effectively dampened E2-dependent Egr1 transcription, and its antagonistic effects were partially interfered with RU486 pretreatment. Interestingly, Egr2 and Egr3 showed similar hormone-dependent expression profiles to that of Egr1 in the uterus. BPA (100 mg/kg) was able to induce immediate expression of Egr1 as effective as E2 at 2 h after treatment. ICI 182,780 and P4 considerably reduced BPA-induced expression of Egr1. In addition, RU486 counteracted inhibitory action of P4 on BPA-induced expression of Egr1. While overall patterns of BPA- induced expression of Egr2 and Egr3 were similar to that of Egr1, BPA was not as effective as E2 for induction of Egr2 and Egr3. BPA could induce phosphorylation of ERK1/2 as well as expression of Egr family members, too. Collectively, these results strongly suggest that BPA as well as E2 can activate concurrent expression profiles of Egr family members via ER-ERK1/2 pathways in the uterus.