• Journal of Radiation Protection and Research
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• v.19 no.3
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• pp.179-188
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• 1994

Mice were whole body irradiated with dose of 2.88Gy and 7.2Gy(Co-60) in order to observe the morphological and functional changes in radio sensitive mouse ovary. Microtechnical sectionates of $7{\mu}m$ thickness from ovary were made for light microscopy and concentrations of progesterone, testosterone and estradiol in ovarian homogenates were analyzed by radioimmunoassay. Gamma radiation resulted in the increase of atretic ratio of preantral and antral follicles, the increase of progesterone concentration in ovarian homogenates, and the low level of testosterone and estradiol. It is suggested that radiation protect the activity of $3{\beta}-HSD$(hydroxysteroid dehydrogenase) and isomerase in the follicular theca cell followed by low level of testosterone and estradiol and thereafter follicular atresia proceed.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1190-1195
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• 2007

This study was conducted to improve efficiency of a follicle culture system without reducing developmental competence of intrafollicular oocytes. Preantral follicles (100 to $125{\mu}m$ in diameter) of F1 hybrid (B6CBAF1) mice were cultured singly for 216 h in modified ${\alpha}$-MEM-glutamax medium, to which 2.5 IU/ml hCG and epidermal growth factor was added 16 h prior to the end of culture. Medium change was either performed three times (54 h interval), twice (72 h interval), once (108 h interval), or not at all (216 h interval). Maturation (progression to the metaphase II stage) of intrafollicular oocytes was detected from 4 days after culture in the three-times change treatment, while all treatments yielded mature oocytes from day 5 of culture. Compared with the three-times change, decreasing the change frequency to once did not reduce the capacity to begin maturation (germinal vesicle breakdown of 82 to 86%), to mature (78 to 79%) and to develop into blastocysts after parthenogenetic activation (29 to 32%). Morphological parameters were similar among these treatments. Except for the no medium change treatment, similar colony-forming activity of inner cell mass cells after culturing of blastocysts in leukemia inhibitory factor-containing medium was detected, while the morphology of the colony-forming cells deteriorated in the change-once treatment compared with the change twice or three-times. In conclusion, the efficiency of the preantral follicle culture system could be improved by reducing frequency of medium change up to a 72 h interval (three times in total 216 h culture) without decreasing developmental competence of oocytes.

• Clinical and Experimental Reproductive Medicine
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• v.36 no.4
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• pp.265-274
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• 2009

Objective: MicroRNAs (miR) are known to repress target genes at post-transcriptional level and play important roles in development and maturation of cell. However, the expression profiles of miR during ovarian follicle maturation have not been fully elucidated. Here, we designed this study to investigate the expression profiles of miR in oocytes and granulose cells (G-cells) after in vitro culture according to gonadotropins and adding hCG. Methods: Ovaries from 12-day-old mice (C57BL6) were removed and preantral follicles were isolated and cultured in $20\;{\mu}L$-drop of culture media with supplementation of either rFSH, rLH, or rFSH+rLH. After their full maturation, follicles were incubated with rhCG and rEGF. RNA was isolated from oocytes and G-cells, and real-time PCR were performed with primers of miR known to be expressed in the mouse ovary (mmu-miR-16, -miR-27a, -miR-126, -miR-721). Results: FSH+LH group showed the highest ovulation and MII rates among gonadotropin groups. The profiles of miRs in oocytes and G-cells differed according to gonadotropin groups and adding hCG. The profiles of miRs showed divergent changes between oocytes and G-cells. Conclusion: miR expression profiles are altered by gonadotropins and supplementation of hCG during in vitro maturation of murine follicles. Target gene study must be necessary to validate these findings.

• Development and Reproduction
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• v.7 no.1
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• pp.49-56
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• 2003

There have been reports that administrated high-dose gonadotropin-releasing hormone-agonist(GnRH-Ag) suppresses endogenous gonadotropin production and inhibits function of ovary. In human IVF-ET program, however, GnRH-Ag is employed in large amounts during superovulation induction resulting to luteal phase defects which must be supported with progesterone. To elucidate the reason of luteal phase defects by GnRH-Ag, the aim of this study was to investigate the apoptosis changes in the ovary and the hormonal changes in the serum after GnRH-Ag and PMSG administration in adult mice in a method similar to human superovualtion induction. GnRH-Ag(10 ${\mu}$g) or saline was injected every 12h beginning 48h prior to PMSG injection until 48h at)or PMSG injection when blood sampling and ovary collection was performed. In results, the ovary weight in the GnRH-Ag only injection group was significantly lower when compared with the other two groups, PMSG only or PMSC + GnRH-Ag injection. The ratio of preantral follicles in the ovary are increased in the GnRH-Ag only group, while the ratio of antral follicles are decreased and the corpus luteum ratio is increased in the PMSG + GnRH-Ag group. The proportion of all follicles showing apoptosis in the GnRH-Ag only in.iection group was seen to be more than twice the proportion seen in the PMSC only injection group, and such increased apoptosis is decreased after addition of PMSC. The serum levels of both estradiol and progesterone were significantly lower in the CnRH-hg only group compared to those in the other two groups. When the administration of GnRH-Ag were followed by PMSG in;ection, however, estradiol concentration was completely recovered compared to the serum level of PMSG group, but not progesterone level. In conclusion the use of GnRH-Ag in human IVF-ET program may induce the apoptosis and the suppression of hormone production by ovary leading to luteal phase defects, thus adequate progesterone support seems to be necessary against them.