CSIRO PublishingActa Medica Okayama103136132972016Expressions of lipoprotein receptors and cholesterol efflux regulatory proteins during luteolysis in bovine corpus luteum12801286ENKeiHorihataLaboratory of Reproductive Physiology, Faculty of Agriculture, Okayama UniversityShinYoshiokaLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama UniversityMasahiroSanoLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama UniversityYukiYamamotoLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama UniversityKojiKimuraLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama UniversityDariusz J.SkarzynskiDepartment of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research, Polish Academy of SciencesKiyoshiOkudaLaboratory of Reproductive Physiology, Faculty of Agriculture, Okayama University The corpus luteum (CL) synthesises and secretes progesterone (P4), which is essential for the establishment and maintenance of pregnancy in mammals. P4 is synthesised from cholesterol. Cholesterol is internalised by low-density lipoprotein receptor (LDLR) and/or scavenger receptor B1 (SR-BI), and is effluxed by ATP-binding cassette (ABC) transporter A1 (ABCA1) and G1 (ABCG1). To test the hypothesis that lipoprotein receptors and ABC transporters are involved in functional luteolysis, we examined the expression of LDLR, SR-BI, ABCA1 and ABCG1 in bovine CL during the luteal stages and after injection of prostaglandin (PG) F2ƒ¿ on Day 10 after ovulation. Expression of LDLR and SR-BI mRNA and protein was lower in the regressed luteal than late luteal stage. Injection of cows with a PGF2ƒ¿ did not affect LDLR mRNA and protein levels in the CL. Although expression of SR-BI mRNA did not change, SR-BI protein expression decreased 12 and 24 h after PGF2ƒ¿ injection. The overall findings of the present study suggest that the decreased expression of SR-BI induced by PGF2ƒ¿ is one of the factors responsible for the continuous decrease in P4 production during functional luteolysis.No potential conflict of interest relevant to this article was reported.CSIRO PublishingActa Medica Okayama1031-361328102015Genomic and non-genomic effects of progesterone on prostaglandin (PG) F2ƒ¿ and PGE2 production in the bovine endometrium15881597ENMarikoKuseLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama UniversityRyosukeSakumotoReproductive Biology Research Unit, National Institute of Agrobiological SciencesKiyoshiOkudaLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama University Progesterone (P4) acts through different actuating pathways called genomic and non-genomic pathways. Here we investigated whether P4 regulates prostaglandin (PG) F2? (PGF) and PGE2 production in bovine endometrium through different pathways. Cultured endometrial cells were exposed to P4 for a short time (5-20min) or bovine serum albumin (BSA)-conjugated P4 (P4-BSA) for 24h. Progesterone treatment for 24h stimulated PGE2 production in epithelial cells, but suppressed both PGF and PGE2 production and the expression of PG-metabolising enzymes including phospholipase A2 (PLA2) and cyclooxygenase-2 (COX2) in stromal cells. Short-term (5-20min) P4 treatment did not affect PLA2 or COX2 transcript levels in either cell type. P4-BSA increased PGF and PGE2 production only in epithelial cells. Nuclear P4 receptor mRNA expression in endometrium was higher at the follicular phase than at the early- to mid-luteal stages, whereas membrane P4 receptor mRNA expression did not change throughout the oestrous cycle. The overall results suggest that P4 controls PG production by inhibiting enzymes via a genomic pathway and by stimulating signal transduction via a non-genomic pathway. Consequently, P4 may protect the corpus luteum by attenuating PGF production in stromal cells and by increasing PGE2 secretion from epithelial cellsNo potential conflict of interest relevant to this article was reported.CSIRO PublishingActa Medica Okayama1031-361328102015Multiple roles of hypoxia in ovarian function: roles of hypoxia-inducible factor-related and -unrelated signals during the luteal phase14791486ENRyoNishimuraLaboratory of Reproductive Endocrinology, Graduate School of Natural Science and Technology, Okayama UniversityKiyoshiOkudaLaboratory of Reproductive Endocrinology, Graduate School of Natural Science and Technology, Okayama University There is increasing interest in the role of oxygen conditions in the microenvironment of organs because of the discovery of a hypoxia-specific transcription factor, namely hypoxia-inducible factor (HIF) 1. Ovarian function has several phases that change day by day, including ovulation, follicular growth and corpus luteum formation and regression. These phases are regulated by many factors, including pituitary hormones and local hormones, such as steroids, peptides and cytokines, as well as oxygen conditions. Hypoxia strongly induces angiogenesis because transcription of the potent angiogenic factor vascular endothelial growth factor (VEGF) is regulated by HIF1. Follicular development and luteal formation are accompanied by a marked increase in angiogenesis assisted by HIF1-VEGF signalling. Hypoxia is also one of the factors that induces luteolysis by suppressing progesterone synthesis and by promoting apoptosis of luteal cells. The present review focuses on recent studies of hypoxic conditions, as well as HIF1-regulated genes and proteins, in the regulation of ovarian function.No potential conflict of interest relevant to this article was reported.CSIRO PublishingActa Medica Okayama1031-36132862014Endothelin as a local regulating factor in the bovine oviduct673681ENYukiYamamotoLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama UniversityMisaKohkaLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama UniversityYoshihikoKobayashiLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama UniversityIzabelaWoclawek-PotockaDepartment of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research, Polish Academy of SciencesKiyoshiOkudaLaboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama University Endothelin (EDN) is a possible regulating factor of oviductal motility, which is important for the transport of gametes and embryo. To clarify the factors that control the secretion of EDN in the bovine oviduct, the expression of EDNs, EDN-converting enzymes (ECEs) and EDN receptors (EDNRs) were investigated. All isoforms of EDN (EDN1-3), ECE (ECE1 and ECE2) and EDNR (EDNRA and EDNRB) were immunolocalised in the epithelial cells of the ampulla and the isthmus. EDNRs were also immunolocalised in smooth-muscle cells. The mRNA expression of EDN2 and ECE2 was higher in cultured ampullary oviductal epithelial cells than in isthmic cells. The expression of EDN1, EDN2 and ECE2 in the ampullary tissue was highest on the day of ovulation. Oestradiol-17ƒÀ increased EDN2 and ECE1 expression, while progesterone increased only ECE1 expression in cultured ampullary epithelial cells. These results indicate that EDNs are produced by epithelial cells and their target site is smooth-muscle and epithelial cells, and suggest that ovarian steroids are regulators of endothelin synthesis in ampullary oviductal epithelial cells.No potential conflict of interest relevant to this article was reported.CSIRO PublishingActa Medica Okayama1031-361329102016Presence of vascular endothelial growth factor during the first half of IVM improves the meiotic and developmental competence of porcine oocytes from small follicles19021909ENTra M. T.BuiDepartment of Animal Science, Graduate School of Environmental and Life Sciences, Okayama UniversityKhánh X.NguyễnDepartment of Animal Science, Graduate School of Environmental and Life Sciences, Okayama UniversityAsakoKarataDepartment of Animal Science, Graduate School of Environmental and Life Sciences, Okayama UniversityPilarFerréDepartment of Animal Science, Graduate School of Environmental and Life Sciences, Okayama UniversityMinh T.TrầnDepartment of Animal Science, Graduate School of Environmental and Life Sciences, Okayama UniversityTakuyaWakaiDepartment of Animal Science, Graduate School of Environmental and Life Sciences, Okayama UniversityHiroakiFunahashiDepartment of Animal Science, Graduate School of Environmental and Life Sciences, Okayama University The aim of the present study was to investigate the effect of vascular endothelial growth factor (VEGF) on the meiotic and developmental competence of porcine oocytes from small follicles (SF; 0.5-3mm diameter). When cumulus-oocyte complexes (COCs) from medium-sized follicles (MF; 3-6mm diameter) and SF were cultured for IVM, the maturation rates were significantly higher for oocytes from MF than SF. Concentrations of VEGF in the medium were significantly higher for COCs cultured from MF than SF. When COCs from SF were exposed to 200ngmL-1 VEGF during the first 20h of IVM, the maturation rate improved significantly and was similar to that of oocytes derived from MF. The fertilisability of oocytes was also significantly higher than that of VEGF-free SF controls. Following parthenogenetic activation, the blastocyst formation rate improved significantly when SF COC culture was supplemented with 200ngmL-1 VEGF, with the rate similar to that of oocytes from MF. The results of the present study indicate that VEGF markedly improves the meiotic and developmental competence of oocytes derived from SF, especially at a concentration of 200ngmL-1 during the first 20h of IVM.No potential conflict of interest relevant to this article was reported.