title: A specific adenylyl cyclase inhibitor (DDA) and a cyclic AMP-dependent protein kinase inhibitor (H-89) block the action of equine growth hormone on in vitro maturation of equine oocytes.
abstract: The objectives of this study were firstly to determine whether the stimulatory function of equine growth hormone (eGH) on equine oocyte maturation in vitro is mediated via cyclic adenosine monophosphate (cAMP); and secondly if the addition of eGH in vitro influences oocyte nuclear maturation and if this effect is removed when GH inhibitors are added to the culture. Cumulus-oocyte complexes (COCs) were recovered from follicles <25 mm in diameter and randomly allocated as follows: (i) control (no additives); and (ii) 400 ng/ml of eGH. A specific inhibitor against cyclic AMP-dependent protein kinase (H-89; 10-9, 10-11 or 10-15 M concentration) and a specific adenylate cyclase inhibitor, 2',3'-dideoxyadenosine (DDA; 10-8, 10-10 or 10-14 M concentration) were used to observe whether they could block the eGH effect. After 30 h of in vitro maturation at 38.5°C with 5% CO2 in air, oocytes were stained with 10 μg/ml of Hoechst to evaluate nuclear status. More mature oocytes (P < 0.05) were detected when COCs were incubated with eGH (29 of 84; 34.5%) than in the control group (18 of 82; 21.9%). The H-89 inhibitor used at a concentration of 10-9 M (4 of 29; 13.8%) decreased (P < 0.05) the number of oocytes reaching nuclear maturation when compared with eGH (11 of 29; 38%). The DDA inhibitor at a concentration of 10-8 M (2 of 27; 7.4%) also reduced (P < 0.05) the number of oocytes reaching maturity when compared with the eGH group (9 of 30; 30%). Results from the present study show that H-89 and DDA can be used in vitro to block the eGH effect on equine oocyte maturation.
authors.affiliation: Animal Science Department,School of Agronomy,Federal University of Rio Grande do Sul,Campus Agronomia,Ave. Bento Gonçalves 7712,Porto Alegre,91540-000,RS,Brasil.
authors.forename: Gabriel Ribas
authors.initials: GR
authors.lastname: Pereira
authors.affiliation: Animal Physiology Department,Veterinary School,Universidad Complutense de Madrid,Madrid,Spain.
authors.forename: Pedro Luis
authors.initials: PL
authors.lastname: Lorenzo
authors.affiliation: Animal Reproduction Department,Garanhuns Academic Unity,Federal Rural University of Pernambuco,Garanhuns,PE,Brazil.
authors.forename: Gustavo Ferrer
authors.initials: GF
authors.lastname: Carneiro
authors.affiliation: Agriculture and Agri-Food Canada Research Centre,Lethbridge,Canada.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Bilodeau-Goeseels
authors.affiliation: Agriculture and Agri-Food Canada Research Centre,Lethbridge,Canada.
authors.forename: John
authors.initials: J
authors.lastname: Kastelic
authors.affiliation: Department of Population Health and Reproduction,School of Veterinary Medicine,University of California,Davis,CA,USA.
authors.forename: Irwin K M
authors.initials: IK
authors.lastname: Liu
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors / Q000494:pharmacology*; D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D016048:Dideoxyadenosine / Q000494:pharmacology*; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D006736:Horses; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods*; D007546:Isoquinolines / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology*
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D007546:Isoquinolines; D047428:Protein Kinase Inhibitors; D013449:Sulfonamides; D016048:Dideoxyadenosine; D013006:Growth Hormone; D017868:Cyclic AMP-Dependent Protein Kinases; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide
keywords: Equine growth hormone; Inhibitors; Meiosis resumption; Oocyte maturation