| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Animal Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, People’s Republic of China
1 State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, People’s Republic of China
(Requests for offprints should be addressed to G Xia; Email: glxiachina{at}sohu.com)
Atrial natriuretic peptide (ANP) as well as its receptors is found in mammalian ovary and follicular cells and its function in oocyte meiotic maturation has also been reported in Xenopus, hamster and rat. But the results are controversial and the physiological mechanism of ANP on oocyte maturation is not clear, especially the relationship between gonadotrophin and ANP as well as the signal transduction, and these need further study. The present study conducted experiments to examine these questions by using drug treatment and Western blot analysis and focused on pig oocyte meiotic maturation and cumulus expansion in vitro. The results revealed that ANP could inhibited FSH-induced pig oocyte maturation and cumulus expansion and prevent the full phosphorylation of mitogen-activated protein kinase in both oocytes and cumulus cells, and that these inhibitory effects could be mimicked by 8-Br-cyclic guanosine 5'-monophosphate (8-Br-cGMP), but blocked by a protein kinase G (PKG) inhibitor KT5823. Zaprinast, a cGMP-specific phosphodiesterase inhibitor, could enhance the inhibitory effect of ANP on oocyte maturation. A specific analogue of ANP, C-ANP-(4–23), which binds to the natriuretic peptide receptor-C (NPRC), had no effect in either FSH-induced or spontaneous oocyte maturation. Treatment with forskolin, a stimulator of adenylate cyclase, had a biphasic effect; 44 h treatment induced cumulus expansion but inhibited oocyte maturation while 2 h treatment induced maturation of cumulus-enclosed oocytes (CEOs). Both ANP and C-ANP-(4–23) could inhibit the effect of forskolin on CEO maturation, and these inhibitory effects of ANP/C-ANP-(4–23) could be blocked by preincubation with pertussis toxin (PT), consistent with mediation by a Gi protein(s) in the cumulus cells. All these results suggest that ANP is a multifunctional regulator of FSH and forskolin on pig CEO maturation by two signalling mechanisms: one is via a cGMP/PKG pathway, the other is via NPRC receptors in cumulus cells and the activation of the PT-sensitive Gi protein(s).
This article has been cited by other articles:
|
|
 |
|
  M. Zhang, H. Ouyang, and G. Xia The signal pathway of gonadotrophins-induced mammalian oocyte meiotic resumption Mol. Hum. Reprod., July 1, 2009; 15(7): 399 - 409. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Sasseville, N. Cote, M.-C. Gagnon, and F. J. Richard Up-Regulation of 3'5'-Cyclic Guanosine Monophosphate-Specific Phosphodiesterase in the Porcine Cumulus-Oocyte Complex Affects Steroidogenesis during in Vitro Maturation Endocrinology, November 1, 2008; 149(11): 5568 - 5576. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Chen, B. Zhou, J. Yan, B. Xu, P. Tai, J. Li, S. Peng, M. Zhang, and G. Xia Epidermal growth factor receptor activation by protein kinase C is necessary for FSH-induced meiotic resumption in porcine cumulus-oocyte complexes J. Endocrinol., May 1, 2008; 197(2): 409 - 419. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
