title: Up-regulation of 3'5'-cyclic guanosine monophosphate-specific phosphodiesterase in the porcine cumulus-oocyte complex affects steroidogenesis during in vitro maturation.
abstract: The 3'5'-cyclic GMP (cGMP) pathway is known to influence ovarian functions, including steroidogenesis, ovulation, and granulosa cell proliferation. We show here that cGMP-phosphodiesterase (PDE) activity increased in a gonadotropin-dependent manner more than 3-fold in the cumulus-oocyte complex (COC) after 24 h in vitro maturation (IVM) and up to 5-fold after 48 h. Further characterization of this increase demonstrated that the activity was located primarily in cumulus cells, and was sensitive to sildenafil and zaprinast, two inhibitors specific to both type 5 and 6 PDEs. RT-PCR experiments showed that the mRNAs for cGMP-degrading PDEs 5A and 6C are present in the COC before and after 30 h IVM. Western blotting confirmed the presence of PDE 5A in the COC. Western blotting of PDE 6C revealed a significant up-regulation in the COC during IVM. Isolation and analysis of detergent-resistant membranes suggested that PDE 6C protein, along with half of the total sildenafil-sensitive cGMP-degradation activity, is associated with detergent-resistant membrane in the COC after 30 h IVM. Treatment of porcine COC with sildenafil during IVM caused a significant decrease in gonadotropin-stimulated progesterone secretion. Together, these results constitute the first report exploring the contribution of cGMP-PDE activity in mammalian COC, supporting a functional clustering of the enzyme, and providing the first evidence of its role in steroidogenesis.
authors.affiliation: Centre de Recherche en Biologie de la Reproduction, Département des Sciences Animales, Université Laval, Québec, Canada G1K 7P4.
authors.forename: Maxime
authors.initials: M
authors.lastname: Sasseville
authors.forename: Nancy
authors.initials: N
authors.lastname: Côté
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Gagnon
authors.forename: François J
authors.initials: FJ
authors.lastname: Richard
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D054885:Cumulus Cells / Q000187:drug effects / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D054678:Cyclic Nucleotide Phosphodiesterases, Type 2 / Q000037:antagonists & inhibitors / Q000235:genetics*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D012739:Gonadal Steroid Hormones / Q000096:biosynthesis*; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D009866:Oogenesis / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011374:Progesterone / Q000378:metabolism; D011687:Purines / Q000494:pharmacology; D011688:Purinones / Q000494:pharmacology; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000494:pharmacology; D013552:Swine / Q000235:genetics*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D012739:Gonadal Steroid Hormones; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D011688:Purinones; D013450:Sulfones; D011374:Progesterone; D000068677:Sildenafil Citrate; D054678:Cyclic Nucleotide Phosphodiesterases, Type 2; C011145:zaprinast; D006152:Cyclic GMP