Inhibition of Polar Body Formation in Mouse Denuded Oocytes Cultured in Vitro by Protein Synthesis Inhibitors

抄録

Denuded oocytes obtained from the ovaries of ddY mice underwent spontaneous germinal vesicle breakdown (GVBD) and polar body formation (PBF) by cultivation for 3 and 16h, successively. To study the significance of protein synthesis in oocytes regarding their maturation, denuded oocytes were cultured in the presence of reversible (cycloheximide and puromycin) and irreversible (ricin) protein synthesis inhibitors. When denuded oocytes were cultivated in the continual presence of any inhibitor, only PBF but not GVBD was found to be inhibited. These inhibitions were dose dependent, ranging from 10^-9 to 10^-6M, and were relative to the protein synthesis inhibitions by them. The PBF inhibition was relieved by withdrawing cycloheximide for first 2, 3 and 4h in the course of the culture. Further, the PBF inhibition occurred in the presence of ricin for only the first 2 or 3h in the course of the culture. These results suggested that proteins synthesized during 2 to 4h in the course of culture may play important roles in PBF.