title: Regulation of Mammalian Oocyte Meiosis by Intercellular Communication Within the Ovarian Follicle.
abstract: Meiotic progression in mammalian preovulatory follicles is controlled by the granulosa cells around the oocyte. Cyclic GMP (cGMP) generated in the granulosa cells diffuses through gap junctions into the oocyte, maintaining meiotic prophase arrest. Luteinizing hormone then acts on receptors in outer granulosa cells to rapidly decrease cGMP. This occurs by two complementary pathways: cGMP production is decreased by dephosphorylation and inactivation of the NPR2 guanylyl cyclase, and cGMP hydrolysis is increased by activation of the PDE5 phosphodiesterase. The cGMP decrease in the granulosa cells results in rapid cGMP diffusion out of the oocyte, initiating meiotic resumption. Additional, more slowly developing mechanisms involving paracrine signaling by extracellular peptides (C-type natriuretic peptide and EGF receptor ligands) maintain the low level of cGMP in the oocyte. These coordinated signaling pathways ensure a fail-safe system to prepare the oocyte for fertilization and reproductive success.
authors.affiliation: Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06030; email: ljaffe@uchc.edu , egbert@uchc.edu.
authors.forename: Laurinda A
authors.initials: LA
authors.lastname: Jaffe
authors.affiliation: Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06030; email: ljaffe@uchc.edu , egbert@uchc.edu.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Egbert
mesh_terms: D000818:Animals; D002450:Cell Communication / Q000502:physiology*; D005260:Female; D006801:Humans; D008322:Mammals / Q000502:physiology*; D008540:Meiosis / Q000502:physiology*; D009865:Oocytes / Q000502:physiology*; D006080:Ovarian Follicle / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology
keywords: cyclic GMP; gap junctions; intercellular communication; luteinizing hormone; oocyte meiosis; ovarian follicle