title: Leptin and ObRa/MEK signalling in mouse oocyte maturation and preimplantation embryo development.
abstract: Recent studies indicate that LH stimulates production of ovarian paracrine factors that induce meiosis of the oocyte. DNA microarray analyses of ovarian transcripts were performed in mice and major increases of a short isoform of leptin receptor, ObRa, were identified by the preovulatory LH/human chorionic gonadotrophin (HCG) surge. In oocytes, the level of ObRa transcripts was increased shortly after HCG stimulation, whereas the level of ObRb transcripts was not changed. Leptin was produced by cumulus, granulosa, theca and interstitial cells of ovaries and its transcript level was not regulated during gonadotrophin treatment. Treatment with leptin promoted germinal vesicle breakdown (GVBD) in oocytes within preovulatory follicles, and enhance first polar body extrusion in both cumulus-oocyte complexes and denuded oocytes. The leptin-promoted GVBD and first polar body extrusion were blocked by a mitogen-activated protein kinase extracellular signal regulated kinase kinases (MEK)1/2 inhibitor, U0126, but not its inactive analogue U0124. Furthermore, leptin promoted fertilization of oocytes and the in-vitro development of zygotes to preimplantation embryos. These findings suggest paracrine roles of leptin in the enhancement of nuclear maturation of oocytes through MEK1/2 signalling, and in the promotion of cytoplasmic maturation essential for successful oocyte development to the preimplantation embryos.
authors.affiliation: Department of Obstetrics and Gynecology, Akita University School of Medicine, Akita, Japan. yeyh1999@hotmail.com
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Ye
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kawamura
authors.forename: Mitsue
authors.initials: M
authors.lastname: Sasaki
authors.forename: Nanami
authors.initials: N
authors.lastname: Kawamura
authors.forename: Peter
authors.initials: P
authors.lastname: Groenen
authors.forename: Maarten D
authors.initials: MD
authors.lastname: Sollewijn Gelpke
authors.forename: Jin
authors.initials: J
authors.lastname: Kumagai
authors.forename: Jun
authors.initials: J
authors.lastname: Fukuda
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D001483:Base Sequence; D001755:Blastocyst; D006063:Chorionic Gonadotropin / Q000097:blood; D017931:DNA Primers; D005260:Female; D007150:Immunohistochemistry; D020738:Leptin / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D051379:Mice; D008813:Mice, Inbred ICR; D020411:Oligonucleotide Array Sequence Analysis; D009865:Oocytes / Q000166:cytology*; D054411:Receptors, Leptin / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction
chemical_list: D006063:Chorionic Gonadotropin; D017931:DNA Primers; D020738:Leptin; D054411:Receptors, Leptin; D007986:Luteinizing Hormone