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.
Motlik
J
J
Department of Genetics, Czechoslovak Academy of Sciences, Libechov.
Nagai
T
T
Kikuchi
K
K
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