title: Promotion of glucose utilization by insulin enhances granulosa cell proliferation and developmental competence of porcine oocyte grown in vitro.
abstract: In vitro culture of the oocyte granulosa cell complexes (OGCs) from early antral follicles (EAFs) shows granulosa cell (GC) proliferation, but to a lesser extent than that observed in vivo during follicle development. As the number of GCs closely relates to energy sufficiency of the oocytes, enhancement of GC proliferation influences oocyte development. GC proliferation depends on glycolysis and insulin-mediated AKT/mTOR signaling pathway; therefore, addition of culture medium containing insulin and glucose may potentially promote GC proliferation and hence improve oocyte development. In the present study, we assessed the effect of exogenous insulin and glucose concentration on GC proliferation and oocyte energy status as well as developmental abilities of porcine oocytes grown in vitro. In the presence of 5.5 mM of glucose (Low), a comparison of 10 versus 20 μg/ml insulin showed that high insulin enhanced GC proliferation but exhausted glucose from the medium, which resulted in low energy status including lipid and adenosine triphosphate of the oocyte. Whereas, in the presence of 20 μg/ml insulin, medium with 11 mM glucose (High) enhanced GC proliferation and oocyte energy status as well as developmental ability up to the blastocyst stage. Considering that there was no difference in OGCs development observed with medium (10 μg/ml insulin) containing 5.5 versus 11 mM glucose, we concluded that the combination of high insulin and glucose enhanced GC proliferation and energy status of oocytes as well as the developmental ability of the oocytes grown in vitro.
authors.affiliation: Department of Animal Science,Tokyo University of Agriculture,Kanagawa 243-0034,Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Itami
authors.affiliation: Department of Animal Science,Tokyo University of Agriculture,Kanagawa 243-0034,Japan.
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Munakata
authors.affiliation: Department of Animal Science,Tokyo University of Agriculture,Kanagawa 243-0034,Japan.
authors.forename: Koumei
authors.initials: K
authors.lastname: Shirasuna
authors.affiliation: Department of Animal Science,Tokyo University of Agriculture,Kanagawa 243-0034,Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Kuwayama
authors.affiliation: Department of Animal Science,Tokyo,University of Agriculture,Kanagawa 243-0034,Japan.
authors.forename: Hisataka
authors.initials: H
authors.lastname: Iwata
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology*; D006107:Granulosa Cells / Q000166:cytology; D059471:In Vitro Oocyte Maturation Techniques; D007328:Insulin / Q000008:administration & dosage / Q000494:pharmacology*; D050356:Lipid Metabolism / Q000187:drug effects; D008055:Lipids / Q000032:analysis; D009865:Oocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013552:Swine
chemical_list: D003470:Culture Media; D007328:Insulin; D008055:Lipids; D005947:Glucose
keywords: Glucose; Granulosa cells; Insulin; Oocytes; Proliferation