Resumption of meiosis in pig oocytes cultured with cumulus and parietal granulosa cells: the effect of protein synthesis inhibition.
In denuded and cumulus-enclosed pig oocytes, puromycin at concentrations 5, 10, and 25 micrograms/ml did not lower the rate of germinal vesicle breakdown (GVBD) after 24 h of culture. GVBD was prevented in 50, 75, and 100 micrograms/ml of puromycin. After 40 h of culture, 5 and 10 micrograms puromycin/ml impaired significantly incidence of metaphase II (42 and 30%), respectively. Concentrations of 25 and 50 micrograms puromycin/ml absolutely prevented the first polar body (I PB) expulsion. The results indicated that GVBD in pig oocytes is far less sensitive to puromycin than I PB expulsion. Culture of cumulus-enclosed pig oocytes isolated with a piece of membrana granulosa (C + P oocytes) did not allow GVBD after 24 and 32 h in control medium. After 24 h of culture, GVBD occurred in 43 and 56% of C + P oocytes in the medium supplemented with 17 and 25 micrograms puromycin/ml. GV was broken down in 80 and 68% of C + P oocytes cultured in 17 and 25 micrograms puromycin/ml for 32 h. It is concluded that inhibition of protein synthesis by puromycin released pig oocytes from the block exerted by granulosa cells.
Department of Genetics, Czechoslovak Academy of Sciences, Libechov.
J
J
Motlik
T
T
Nagai
K
K
Kikuchi
D000818:Animals; D002478:Cells, Cultured / Q000187:drug effects; D005260:Female; D006107:Granulosa Cells / Q000166:cytology* / Q000187:drug effects; D008540:Meiosis / Q000187:drug effects; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects; D006080:Ovarian Follicle / Q000166:cytology* / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D011691:Puromycin / Q000494:pharmacology*; D013552:Swine
D011500:Protein Synthesis Inhibitors; D011691:Puromycin