Development of haploid and diploid mouse parthenogenones: effect of oocyte aging in vivo

Mouse oocytes were collected 13.5-29.5 hr after hCG injection at 4 hr intervals, then activated with 7% ethanol for 1 min. The oocytes collected 13.5 hr after hCG injection did not respond to ethanol activation. High activation rates (90.2-98.3%) were obtained in oocytes activated 17.5-29.5 hr after injection with hCG. Haploid parthenogenones were dominant though the number decreased as the age of oocytes advanced (89.5% to 42.0%). The highest number of diploid parthenogenones (20.6%) was obtained in oocytes activated 21.5 hr after hCG injection. The number of immediate cleavage and morphologically abnormal oocytes increased when the oocyte age progressed (0.7% to 34.7% and 1.1% to 23.2%, respectively). The percentage of parthenogenones developing to blastocysts decreased with the increase in oocytes age: haploid 51.9% to 1.4% and diploid 100.0% to 83.3%. The present study demonstrates that the developmental potentials of haploid and diploid parthenogenones derived from oocytes at 17.5 and 21.5 hr are higher than those derived from oocytes at 25.5 and 29.5 hr after hCG injection.