• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.240-240
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• 2004

The modification of in vitro maturation (IVM) conditions should be required to efficient production of matured porcine oocyte in vitro. Estradiol-17β (E₂) as steroid hormone exists in ovarian follicular fluid and plays a major role in ovulation. It has been reported that estradiol as well as other steroids are involved in keeping the oocytes in meiotic arrest. (omitted)

• Journal of Embryo Transfer
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• v.29 no.2
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• pp.195-200
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• 2014

Endothelin 2 (EDN2) induces follicular rupture by constricting periovulatory follicles. In this study, it was investigated the mechanisms of EDN2 action on follicular rupture with respect of receptor using the conditionally granulosa cell specific EDN2 receptor type A (ETa) KO mice (gcETaKO; $ETa^{flox/-}{\cdot}Amhr2^{Cre}$). It was generated the gcETaKO mice by breeding with $ETa^{flox/-}$ mice after mono-alleic ETa knockout by $ZP3^{Cre}$ and $Amhr2^{Cre}$ mice. Fertility, ovulation and maturation rates of ovulated oocytes after super ovulation were investigated in the gcETaKO mice compared with wild-type mice ($ETa^{flox/flox}$ and $ETa^{flox/-}$) as a control group. In the gcETaKO mice, normal fertility after breeding with male mice was shown compared with wild-type mice. And, there was no significant differences in ovulation rates after super ovulation, however its maturation rates was lower than that of wild type mice. These findings show that EDN2 in follicular rupture for ovulation is related with an other ETa not in granulosa cells. Further studies are needed to investigate how EDN2 is acted in ovarian follicular rupture for ovulation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.8-16
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• 1998

Sexual maturation and reproductive cycle of the goldeye rockfish, Sebastes thompsoni were investigated under photomicroscopy. Samples were collected monthly in the coastal water of Samcheonpo ($34^{\circ}55'N$ ), Korea from November 1995 to October 1996, The ovary consists of several ovarian lamellae originated from ovarian outer membrane. Oogonia which are originated from the inner surface of the ovarian lamella protrude to the ovarian cavity in oocyte stage, and they ave suspended by the egg stalk. The testis is seminiferous tubule type in internal structure. Seminiferous tubule consists of many testicular cysts which contain numerous germ cells in same developmental stage. Biological minimum size of female and male were 19.5 cm and 21.5 cm in total length, respectively. Gonadosomatic index (GSI) of female was the highest (9.56) in March and the lowest (0.15) in August. GSI of male was the highest (0.25) in February and the lowest (0.04) in July. Reproductive cycle was classified into the following successive stages: in female, growing (October and November), maturation ( $December\~February$), gestation (March), parturition and recovery ($April\~June$) and resting ($July\~September$), and in male, growing ($September\~November$), maturation ( December and January), ripe and copulation ( February and March) and degeneration and resting ($April\~August$).

• Korean Journal of Agricultural Science
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• v.34 no.1
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• pp.13-18
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• 2007

This study was carried out to investigate the effects of ovarian estrus stage of oocytes and supplementation of medium with BSA, cysteine and myoinositol on in vitro maturation of canine oocytes. The in vitro maturation(IVM) rate to metaphase II (M II) stage of oocytes recovered from different stage of the reproductive cycle (inactive, follicular and luteal stage) cultured in TCM-199 media were $0.0{\pm}0.0%$, $10.0{\pm}4.1%$ and $5.7{\pm}1.6%$, respectively. The IVM rate of oocytes collected from follicular stage was significantly higher in inactive or luteal stage of oocytes. The IVM rates of oocytes recovered from different stage of the reproductive cycle cultured in TCM-199 media with 5% BSA and 0.1 mM cysteine were$0.0{\pm}0.0%$, $15.8{\pm}4.7%$, $5.6{\pm}1.5%$, respectively. The IVM rates of oocytes recovered from different stage of the reproductive cycle cultured in TCM-199 media with 5% BSA and 10 mM myoinositol were $0.0{\pm}0.0%$, $18.4{\pm}4.6%$ and $5.7{\pm}1.9%$, respectively. The IVM rate of follicular stage oocytes was significantly higher in oocytes collected from follicular stage and with cultured 5% BSA and 0.1 mM cysteine or 5% BSA and 10 mM myoinositol compared to other experimental group.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.31-35
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• 2007

The main purpose of this study was to improve the efficiency and quality of in vitro embryo production in Korean Native Cows (KNC). We examined the effects of ovarian morphologies (Experiment 1) and the culture vessel (Experiment 2) on in vitro maturation (IVM). We measured the subsequent development rates and cell numbers of blastocysts. In Experiment 1, the ovaries of KNC were divided into six groups, based on follicle and corpus luteum (CL) morphology. The development rates to the 2- and 8-cell stages were similar among the six groups. The development rates to blastocyst stages were significantly higher in the group without a CL or follicle (WOCL/F) than in the groups with follicular cysts (FCs), regressive CLs (RCLs) or cystic CLs (CCLs) (p<0.05). The cell number of the inner cell mass (ICM) of blastocysts in the FCs and RCLs groups, and the number of cells in the trophectoderm (TE) in the WOCL/F group, FCs, growing CLs (GCLs) and RCLs were significantly higher than in other groups (p<0.05). The total cell number (TCN) in the WOCL/F, FC and RCL groups was also significantly higher than in other groups (p<0.05). The ICM cell number/TCN ratio was significantly higher in the FC and RCL groups than in the GCL and DF groups (p<0.05). In Experiment 2, oocyte IVM was carried out in culture dishes, in 0.25- or 0.5-ml straws used for freezing sperm. The development rate to the 2-cell stage was significantly higher in the 0.5-ml straw group than in the 0.25-ml straw group. The development rates to the blastocyst stage were similar in the dish and the two straw groups. There were no differences in the cell numbers of ICM, TE or TCN or ICM cell number/TCN ratios between groups.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.174-178
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• 2004

The objectives of this study were to investigate the ovarian responsiveness of juvenile calves to exogenous gonadotropin treatments and to establish the oocyte retrieval technique for prepubertal heifers. Three 78-day-old calves were treated with 4 doses (40, 30, 30 and 30 mg) of FSH (Folltropin V) at 12 h interval up to 229 day-old. Surgical oocyte retrieval was performed 24 h after the last injection of FSH. Calves with good ovarian responses to FSH treatment had an average ovarian size of $5{\times}3$ cm compared to $3{\times}2$ cm in the less-responsive animals. Large variations were observed in the number of total follicles ($51{\pm}45$), aspirated follicles ($39{\pm}36$), oocytes recovered ($23{\pm}25$) and usable oocytes recovered ($11{\pm}19$) during 78 to 229 day-old. Oocytes derived from prepubertal calves had significantly lower maturation rate than those from cows (34 vs. 100%, p<0.05). Mean diameters of calf oocytes ($144{\pm}1{\mu}m$) and ooplasm ($110{\pm}1 {\mu}m$) were significantly lower than those of cows ($149{\pm}1$ and $25{\pm}1{\mu}m$, respectively). The diameter of the ooplasm also increased significantly after in vitro maturation (IVM) ($108{\pm}1$ vs. $112{\pm}1{\mu}m$). However, further studies are required to optimize the IVP system for the oocytes derived from prepubertal heifers.

• Animal cells and systems
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• v.11 no.2
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• pp.117-124
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• 2007

The present study demonstrates the changes in body weight (BW) and plasma sex steroid hormone profiles during artificial maturation induced by human chorionic gonadotropin (HCG) or salmon pituitary extract (SPE) injections in cultured eel, Anguilla japonica, kept in seawater for 3 months. In the weekly SPE-injected female group, BW was relatively stable during vitellogenesis. Following induction of vitellogenesis, females exhibited a rapid increase of BW, and the oocytes were observed to be in the migratory nucleus stage at the end of the experiment. Plasma testosterone (T) and $estradiol-17{\beta}$ ($E_2$) levels increased slightly during vitellogenesis and peaked at an average of 5.82 ng/mL and 4.76 ng/mL, respectively, at the end of the experiment. In the weekly control and HCG-injected female groups, BW slowly decreased during the experimental period, and the oocytes of the two groups were observed to be at the primary yolk globule stage. In the weekly HCG-injected female group, plasma T and $E_2$ levels increased slightly during vitellogenesis and decreased afterward. In the control female group, however, plasma T and $E_2$ levels were not altered during the experimental period. Furthermore, plasma $17{\alpha},20{\beta}-dihydroxy-4-pregnen-3-one$ (DHP) was not detected in all experimental groups. Fertility and hatching rates of SPE-injected females were significantly higher in those that ovulated 15 h after DHP injection than 18 h. These results indicate that long rearing in seawater increases responsiveness to SPE in ovarian maturation of the Japanese eel, resulting in shortened period from completion of vitellogenesis by sex steroid hormone production.

• Animal cells and systems
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• v.5 no.1
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• pp.45-50
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• 2001

Rana ovarian follicles consist of oocyte, vitelline envelope, granulosa cells, and theca/epithelial layer. Using scanning electron microscopy, the surface structure of each follicular component was investigated. Changes in oocyte surface during oocyte maturation were also examined. Theca/epithelial layer was almost transparent and some blood vessels and granulosa cells were observed underneath in intact follicle. The number of granulosa cells was estimated to be 6700-7200 per oocyte. The granulosa cells partially overlapped each other and their microvilli penetrated the vitelline membrane via holes present in the vitelline envelope and seemed to be linked to oocyte microvilli. After removal of the vitelline envelope by microforcep, oocyte microvilli were observed on the surface of the devitellined oocyte. The oocyte microvilli formed partial clusters on the surface of white spot area which appears iust before germinal vesicle breakdown (GVBD), whereas they were evenly distributed in other areas. The microvilli became shorter and less dense with oocyte maturation. The lengths of oocyte microvilli in the immature and mature oocyte were 1.5 $\mu$m and 0.6 $\mu$m, respectively. The present study suggests a fundamental structural change occurring on the oocyte surface during maturation.

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.145-150
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• 2009

This study was conducted to examine the effects of human follicular fluid and gonadotropin (FSH+HCG+rhEGF) on in vitro maturation, fertilization and development of human immature oocytes. Cumulus-oocyte complexes (COCs) were collected following for in vitro fertilization and embryo transfer (IVF-ET) cycles of the patients. At the time of oocytes collection, oocytes were classified into MII, MI and GV in accordance with their appearance (MII: Fully mature oocyte at metaphase II of meiosis; MI: Nearly mature oocytes at metaphase I of meiosis; GV: Immature oocytes at prophase I of meiosis). After controlled ovarian stimulation using gonadotropin(FSH) and human chorionic gonadotropin (HCG) in 70 ICSI cycles, 158 MI to MII matured oocytes were intracytoplasmic sperm injection (ICSI) ${\sim}4$ h after in vitro culture and 553 MII oocytes were ICSI after denudation. The aspirated MI and GV oocytes were cultured in culture medium containing 10% (v/v) serum protein substitute (SPS), 10% (v/v) human follicular fluid (hFF) and 10% (v/v) serum protein substitute (SPS)+1 IU/ml FSH+10 IU/ml HCG+10 ng/ml recombinant human epidermal growth factor (rhEGF). The maturation rate of immature oocytes was similar among the three group. When maturation medium was supplemented with 10% SPS, 10% hFF or gonadotropins, the fertilization rate of in vitro matured oocytes was higher in 10% SPS (80.0%), but there was no statistical significance (78.2%; hFF, 76.9%; gonadotropin, p>0.05). The development rate of human embryos developed to $6{\sim}8$ cells were not significant difference in the medium containing SPS, hFF and gonadotropins (65.6%, 65.9% and 66.7%). The results of these study suggest that human follicular fluid and gonadotropins supplemented in the culture medium was not effected on the in vitro maturation, fertilization and development of human immature oocytes.

• Korean Journal of Agricultural Science
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• v.35 no.2
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• pp.167-176
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• 2008

Supplementation of serum and estrogen in in vitro maturation(IVM) medium was shown to improve embryo development and quality in several species. This study investigates the effect of ovarian estrus stage on canine oocyte quality and supplementation of medium with canine serum or estrogen on IVM of canine oocytes. As results, in experimental 1, IVM oocytes collected from follicular stage ovaries to MII stages($10.2{\pm}1.5%$) was higher (p<0.05) with 10% canine estrus stage serum than control($1.3{\pm}1.6%$), anoestrus stage serum($4.0{\pm}1.6%$), luteal stage serum($2.7{\pm}1.7%$) and 10% FBS($1.3{\pm}1.6$). In experimental 2, 10% canine estrus stage serum supplementation has highest maturation rate to MII stages($10.0{\pm}1.8%$) and there were significant differences(P<0.05) with another treatment in follicular stages group. In order to investigate the synergic effect of estrous serum and estrogen supplementation, different estrous stage groups of oocytes were cultured with 2 ug/ml estrogen plus various concentrations of different reproductive stage serum and FBS(experimental 3). As results, the rate of maturation to metaphase II(MII) stage was significantly higher(p<0.05) in oocytes from the follicular stage supplemented with estrogen and 10% canine estrus stage serum(11.5%) compared to the other groups(6.0 - 8.8%). The present study was demonstrated that canine serum and the estrus cycle of the bitch affect the meiotic competence of oocytes. Hormonal influences within the follicle may be one of the factors responsible for the greater proportion of maturation of oocyte to MII from bitches at the follicular phase.