title: Reversible meiotic arrest in feline oocytes.
abstract: Increasing intracellular concentrations of cyclic adenosine monophosphate (cAMP) within the cumulus-oocyte complex (COC) inhibits or delays spontaneous oocyte maturation and improves the developmental competence of the oocyte in many species, but information for carnivores is limited. The objectives of the present study were to describe the effects of isobutyl methylxanthine (IBMX), which decreases cAMP degradation, and forskolin, which increases cAMP production, on spontaneous and induced maturation (by equine chorionic gonadotrophin (eCG) and epidermal growth factor (EGF)) of feline oocytes and to evaluate the reversibility of IBMX-induced arrest by measuring the resumption of meiosis and embryonic development following IVF. IBMX decreased (P<0.05) the incidence of spontaneous (6.7% vs 42.0%, metaphase II (MII)) and induced (5.6% vs 66.1% MII) maturation after 24 h of culture. In contrast, forskolin stimulated meiosis (81.7% MII; P<0.05). Following 12 h of culture with IBMX and an additional 24h with eCG and EGF in the absence of IBMX, the proportions of oocytes reaching MII (66.1%), cleaving (79.9%) and developing to the blastocyst stage (15.3%) were similar (P>0.05) to oocytes cultured continuously with eCG and EGF (70.2%, 83.0% and 18.1%, respectively). These results demonstrate that IBMX reversibly inhibits both spontaneous and eCG+EGF-induced meiosis in feline oocytes without compromising the oocyte's developmental competence.
authors: Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL 61802, USA.Present address: National Foundation for Fertility Research, 10290 RidgeGate Cr, Lone Tree, CO 80124, USA. Email:
authors: Jason R
authors: JR
authors: Herrick
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology*; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000378:metabolism; D002415:Cats; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D046149:Embryo Culture Techniques; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005260:Female; D005307:Fertilization in Vitro; D059471:In Vitro Oocyte Maturation Techniques; D059566:M Phase Cell Cycle Checkpoints / Q000187:drug effects*; D008540:Meiosis / Q000187:drug effects*; D009865:Oocytes / Q000187:drug effects* / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D006063:Chorionic Gonadotropin; D020536:Enzyme Activators; D010726:Phosphodiesterase Inhibitors; D005576:Colforsin; D004815:Epidermal Growth Factor; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D015056:1-Methyl-3-isobutylxanthine