earticle

영어

Estrogen plays a critical roles in may reproductive process such as maturation of ovarian follicles, embryo implantation, placentation, lactation, parturition, sexual differentiation, and sexual behavior in females. It is well known that estrogen binds to nuclear estrogen receptors, ERα and ERβ, which mediates the genomic signaling pathway. However, it has been shown that G protein-coupled estrogen receptor 1 (GPER1), one of the estrogen receptors, exists on the cell membrane and induces non-genomic action. In the mouse uterus, GPER1 is known to mediate oocyte maturation, endometrial cell growth and myometrial contraction. However, the expression and regulation of GPER1 has not been determined in the uterine endometrium in pigs. Thus, this study investigated expression of GPER1 in the uterine endometrium during the estrous cycle and pregnancy in pigs. We obtained the endometrial tissues from gilts on day (D) 0, D3, D6, D9, D12, D15 and D18 of the estrous cycle and on D12, D15, D30, D60, D90 and D114 of pregnancy, and chorioallantoic tissues on D30, D60, D90 and D114 of pregnancy. GPER1 mRNA was expressed in the uterine endometrium during the estrous cycle and pregnancy in pigs. During the estrous cycle, levels of GPER1 mRNA in diestrus and proestrus were higher than those in estrus and metestrus. Levels of GPER1 mRNA on D15 of the estrous cycle was significantly higher than those on D15 of pregnancy. Levels of GPER1 mRNA decreased during mid- to late pregnancy. RT-PCR analysis showed that GPER1 mRNA was not detectable in conceptus on D12 and D15 of pregnancy. In the chorioallantoic tissues, GPER1 mRNA was expressed during mid- to term pregnancy and level of mRNA increased toward term pregnancy. Endometrial explant culture study showed that increasing doses of estradiol-17β did not affect the expression of GPER1, but increasing doses of progesterone down-regulated the expression of GPER1 mRNA. These results indicate that GPER1 mRNA is expressed in the uterine endometrium during the estrous cycle and pregnancy in a stage- and pregnancy status-dependent manner, suggesting that in addition to nuclear ERs, GPER1 may play an important role in the porcine uterus. Further analysis of localization and signaling pathway of GPER1 in the uterine endometrium is needed.