@article{oai:niigata-u.repo.nii.ac.jp:00028407, author = {Takano, Hiroko and Niimura, Sueo}, issue = {2}, journal = {新潟大学農学部研究報告, 新潟大学農学部研究報告}, month = {Mar}, note = {We formerly reported in porcine oocytes that cortical granules (CGs) move to the cytoplasm immediately beneath the plasma membrane as nuclear maturation progresses, and that the movement of CGs and the resumption of meiotic division do not occur in those treated with olomoucine. Therefore, we suggested that CGs distribution in the cytoplasm is closely associated with nuclear maturation. However, whether olomoucine directly acts on the cytoplasm to inhibit such change in CGs distribution could not be determined. In the present investigation, the distribution of CGs was lectin-histochemically observed in porcine oocytes treated with IBMX or dbcAMP, which suppresses the nuclear maturation with the mechanism different from olomoucine, and also in porcine oocytes treated with olomoucine and dbcAMP, in order to examine the relationship between nuclear maturation and the distribution of CGs in the cytoplasm. Nuclei of the oocytes cultured for 22 hrs with IBMX, dbcAMP, or olomoucine and dbcAMP were all in the germinal vesicle (GV) stage. The percentages of oocytes in the GV stage were significantly higher in the treated oocytes than in control oocytes. CGs in the oocytes treated with IBMX, dbcAMP, or olomoucine and dbcAMP were distributed in the cortical cytoplasm and also immediately beneath the plasma membrane. The distribution of CGs in such the treated oocytes did not differ from those of control oocytes. From these results, it was suggested that the changes in the distribution of CGs in the cytoplasm with oocyte maturation depend on the cAMP level in their cytoplasm rather than the progression of nuclear maturation.以前我々は、ブタ卵母細胞において、表層粒は核の成熟に伴って細胞膜直下の細胞質に移動するとともに、核の成熟をオロモウシンで処置して阻止した卵母細胞ではこのような表層粒の分布変化はみられなかったことから、表層粒の分布変化と核の成熟とは密接に関係していることを推察して報告した。しかし、オロモウシンが表層粒の分布変化に直接関係しているのか否かは明らかにできなかった。そこで、オロモウシンとは異なった機構、すなわち細胞質のcAMPレベルを高く維持することによって核の成熟を抑制する作用のあるIBMXとdbcAMPを用いて、ブタの卵母細胞を処置し、表層粒の分布変化をレクチン組織化学的に観察した。IBMX、dbcAMPあるいはオロモウシンとdbcAMPで22時間処置した卵母細胞において、核はすべてが卵核胞期にあり、これらの処置により成熟分裂が抑制されていることが確認された。一方、IBMX、dbcAMPあるいはオロモウシンとdbcAMPで22時間処置した卵母細胞において、表層粒は、細胞質の表層および細胞膜直下の細胞質に分布しており、対照の卵母細胞における分布と相違なかった。以上の結果から、細胞質における表層粒の分布は、核の成熟の進行よりも、細胞質のcAMPの量に依存して変化することが推察された。}, pages = {123--128}, title = {Nuclear Maturation and Cortical Granule Distribution in Porcine Oocytes Treated with IBMX and dbcAMP}, volume = {60}, year = {2008} }