title: Influence of epidermal growth factor on mammalian oocyte maturation via tyrosine-kinase pathway.
abstract: Epidermal growth factor (EGF) has been reported to promote different functions in mammalian ovaries, including oocyte maturation. The aim of the present study was to establish: that EGF influences oocyte maturation in ovine and equine, that a tyrosine kinase-dependent intracellular mechanism mediates EGF effect and, that EGF-R receptor is detectable in ovarian follicles by immunohistochemistry methods. Selected ovine and equine oocytes were aspirated from 2-5 mm (ovine) or 25 mm (equine) follicles and cultured in TCM 199 for 22 (ovine) or 36 hours (equine). They are then subjected to culture with EGF and two specific tyrosine-kinase inhibitors (TKIs, tyrphostins A-23 y A-47). Maturation was determined as the percentage of oocytes at metaphase II stage after culture. Treatments with EGF significantly increased incidences of metaphase II stage compared to controls (86.2% vs. 55% and 70.4% vs. 22.5% in ovine and equine oocytes, respectively). Tyrphostins A-23 and A-47 were effective in suppressing EGF-effect on oocytes. EGF-receptor was localized in follicles, being more prominent in cumulus and granulosa cells. These results confirm that EGF has a physiological role in the regulation of oocyte maturation via tyrosine-kinase pathway.
authors.affiliation: Departamento de Fisiología Animal, Facultad de Veterinaria, Univ. Complutense, Madrid, Spain. lorenzopl@vet.ucm.es
authors.forename: P L
authors.initials: PL
authors.lastname: Lorenzo
authors.forename: I K
authors.initials: IK
authors.lastname: Liu
authors.forename: J C
authors.initials: JC
authors.lastname: Illera
authors.forename: R A
authors.initials: RA
authors.lastname: Picazo
authors.forename: G F
authors.initials: GF
authors.lastname: Carneiro
authors.forename: M J
authors.initials: MJ
authors.lastname: Illera
authors.forename: A J
authors.initials: AJ
authors.lastname: Conley
authors.forename: A C
authors.initials: AC
authors.lastname: Enders
authors.forename: M
authors.initials: M
authors.lastname: Illera
mesh_terms: D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000502:physiology*; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D006736:Horses; D007150:Immunohistochemistry; D009865:Oocytes / Q000254:growth & development*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013552:Swine
chemical_list: D004791:Enzyme Inhibitors; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases