Inhibitory effects of cAMP and protein kinase C on meiotic maturation and MAP kinase phosphorylation in porcine oocytes.
The regulation of MAP kinase phosphorylation by cAMP and protein kinase C (PKC) modulators during pig oocyte maturation was studied by Western immunoblotting. We showed that both forskolin and IBMX inhibited MAP kinase phosphorylation and meiosis resumption in a dose-dependent manner, and this inhibitory effect was overcome by the protein phosphatase inhibitor, okadaic acid. Pharmacological PKC activator phorbol myristate acetate or physiological PKC activator diC8 also delayed MAP kinase phosphorylation and meiosis resumption, and their effect was abrogated by PKC inhibitors, staurosporine, and calphostin C. The results suggest that meiotic resumption is inhibited by elevation of cAMP or delayed by activation of PKC probably via down-regulation of MAP kinase activation, which is mediated by protein phosphatase, during pig oocyte maturation.
Fan
Heng-Yu
HY
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China.
Li
Man-Yu
MY
Tong
Chao
C
Chen
Da-Yuan
DY
Xia
Guo-Liang
GL
Song
Xiang-Fen
XF
Schatten
Heide
H
Sun
Qing-Yuan
QY
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology*; D004075:Diglycerides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D008540:Meiosis / Q000187:drug effects*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism*; D013552:Swine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004075:Diglycerides; D004791:Enzyme Inhibitors; C044295:1,2-dioctanoylglycerol; D000242:Cyclic AMP; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate; D015056:1-Methyl-3-isobutylxanthine