Progesterone regulates endometrial functions to support implantation, placentation, and fetal/placental development in the uterus. It is known that actions of progesterone are mediated by nuclear progesterone receptor (PGR), using the signaling pathway referred to the genomic pathway. However, all physiological progesterone actions cannot be explained by the genomic pathway via PGR, and it is understood that there are non-genomic actions of progesterone though membrane progesterone receptors, progesterone receptor membrane components (PGRMCs) and progestin and adipoQ receptors (PAQRs). The expression and localization of PGRMCs and PAQRs has been reported in female reproductive tissues of several species such as human, mouse and cattle. Previously, we have shown that PGRMCs and PAQRs are expressed in the porcine uterine endometrium during the estrous cycle and pregnancy. However, the regulatory mechanism for expression of PGRMCs and PAQRs in the uterine endometrium has not been studied in pigs. Thus, to understand the regulatory mechanism of PGRMC1, PGRMC2, PAQR5, PAQR6, PAQR7, PAQR8, and PAQR9 expression in the uterine endometrium during the estrous cycle and pregnancy in pigs, we determined the effect of steroid hormones estrogen and progesterone on expression of PGRMCs and PAQRs using the endometrial tissue explants for immature pigs. Levels of PGRMC1, PGRMC2, PAQR5, PAQR6, PAQR7, PAQR8, and PAQR9 mRNAs were increased by increasing doses of progesterone, but not by estradiol in the uterine endometrium. Blocking PGR by treatment of RU486, a progesterone receptor antagonist, increased levels of endometrial PGRMCs and PAQRs mRNA. These data showed that membrane progesterone receptors were induced by progesterone in the uterine endometrium, suggesting that these membrane progesterone receptors may play an important role in mediating progesterone actions in the uterine endometrium for regulation of the estrous cyclicity and pregnancy. [Supported by the Next Generation Biogreen 21 Program (# PJ01119103), Rural Development Administration, Republic of Korea]

The greater horseshoe bat (Rhinolophus ferrumequinum) is distributed throughout Europe, Africa, Australia, and South Asia. It habits mainly in the cave in small groups and forming communities in late spring. It has interesting reproductive behavior because it keeps sperm for a few months in female reproductive tracts and then those sperms attend in fertilization. This breeding pattern is a sperm storage type and belongs to Rhinolophidae or Hipposideridae. The greater horseshoe also habits in Korea. However, the reasons of reproductive behaviors has not much uncovered. In this study the characters of ovary and the levels of steroid hormones were investigated from September to November. The histological, ELISA, and immunohistochemical methods were employed. The pre-ovulatory follicle was detected only at October sample. On the other hand, the blood level of testosterone was not detectable but the levels of 17β-estradiol and progesterone were exist within the detectable range. E2 and P4 levels were peak in October. Besides, the key enzymes for estradiol synthesis, CYP17 and CYP19 were localized in the theca layer and granulosa cells, respectively. October is known as mating time in this species. However, progesterone receptors could not detect at this period. Put together, it is suggested that, the increase of estrogen and the absence of progesterone receptors on preovulatory follicle is the cause of the mating without ovulation. The understanding of the expression regulation in this system will be base of the understanding the anovulation in mammals.