• Reproductive and Developmental Biology
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• v.28 no.4
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• pp.267-273
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• 2004

Maturation of oocytes is maintained by complex procedures along with follicular genesis and is a critical step for embryonic development. Purine known as an oocyte maturation regulator is present in follicular fluid. In this study, the roles of guanosine as a strong inhibitor of GVBD and a modulator of cyclic GMP concentration in ooyctes were revealed. Denuded immature oocytes were treated with guanosine, and the maturation rates and cGMP concentration of oocytes were measured. GVBD was blocked in a concentration dependent manner by guanosine, but this effect was reversible. However, GVBD was lagged yet not significant by adenosine. Both guanosine and adenosine modified cGMP concentration in oocytes. The characteristic of the guanosine-treated oocyte was significantly higher cGMP compared with the adenosine-treated oocyes at initial time of the maturation. Based these results, guanosine may be a strong and reversible GVBD inhibitor. Although the precise mechanism of guanosine presently is unclear, the results suggest that guanosine may lead the accumulation of cGMP in oocyte cytoplasm, which in turn suppresses GVBD.

• Journal of Embryo Transfer
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• v.21 no.1
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• pp.7-11
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• 2006

개 난자의 체외성숙과 체외수정을 통해 수정란을 획득하기 위하여 개 난소를 채취하여 난자의 형태, 난소의 채취시기 등이 체외성숙과 체외수정에 미치는 영향을 구명하기 위하여 수행하였다. 1. 난구세포 부착 및 미부착 난자를 48시간 배양했을 때 체외 성숙율은 $42.0{\pm}3.4%,\;24.4{\pm}4.1%$였다. 난구 세포 부착 난자의 체외 성숙율이 미부착 난자의 체외 성숙율보다 유의하게 높게 나타났다(p>0.05). 2. 난소를 휴지기, 난포기 및 황체기로 구분하여 난자를 회수하여 배양했을 때 체외 성숙율은 각각 35.6%, 50.0%, 31.1%였고 체외 발생율은 각각 2.2%, 20.0% 및 8.9%로서 난구 세포 부착 난자가 미부착 난자에 비해 유의한 체외 수정율을 나타냈다. 3. 난구세포 부착 및 미부착 난자를 이용하여 체외수정시켰을 때 체외 수정율과 체외 발생율은 각각 48.0%, 35.6% 및 22.5%, 13.3%로서 난구세포 부착 난자가 미부착 난자에 비해 유의하게 높게 나타났다.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.3
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• pp.285-296
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• 1994

Follicular oocytes were released from the graafian follicles of ovaries from 3-4 weeks old mice. The spontaenous maturation of these follicular oocyes was inhibited by the treatment of dbcAMP and progesterone and these oocytes were cultured for 2-8hr in the Modified Hank's balanced salt solution(MHBS). Ethylenediaminetetraaceticacid(EDTA) and calmoudulin antagonist, trifluoperazine (TFP) were treated to the culture medium in order to investigate whether these chemical agents inhibit calcium uptake into the oocyte and oocyte maturation. $^{45}Ca^{2+}$, 10-${\mu}$Ci/ml was added to the culture medium during the culture period. $^{45}Ca^{2+}$uptake into the oocytes was examined whether and when various kind of oocyte maturation inhibiting agents inhibit or stimulate the influx of calcium into oocytes. Dibutyryl cAMP and progesterone decrease $^{45}Ca^{2+}$uptake into the oocytes and synergistic inhibiting effect of dbcAMP and progesterone was prominent at much lower dosages. Calcium uptake into oocytes seems to be higher during first 2 hour culture period rather than next 4hr culture. After 8hr culture, calcium uptake level of the oocytes which GVBD already took place gradually approached to the level of those which were maintained at GV by the treatment of dbcAMP and progesterone. However, $^{45}Ca^{2+}$uptake into the GV maintained oocytes did not change at all even after 8hr culture period. In addition, calcium chelating agent, EDTA inhibited calcium uptake into oocytes as well as nuclear maturation of oocytes. Lower dosage used in the present study did not inhibit calcium uptake as well as oocyte maturation.