• 한국발생생물학회지:발생과생식
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• 제20권4호
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• pp.359-365
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• 2016

Intact germinal vesicle (GV) arrest and release are essential for maintaining the fertility of mammals inducing human. Intact germinal vesicle release, maturation of oocytes is maintained by very complex procedures along with folliculogenesis and is a critical step for embryonic development. Cyclic guanosine monophosphate (cGMP) has been suggested a key factor for meiotic arrest but so far its mechanisms are controversy. In this study we examine the effects of cGMP on germinal vesicle breakdown in cumulus-enclosed oocytes and denuded oocytes. Spontaneous maturation was inhibited by a cGMP agonist, 8-Br-cGMP with concentration dependent manners both in cumulus-enclosed oocytes and denuded oocytes. The inhibitory effect was more severe in denuded oocytes than cumulus-enclosed oocytes. The Rp-8-Br-cGMP and Rp-pCPT-8-Br-cGMP did not severely block GVB compared to 8-Br-cGMP. The spontaneous GVB inhibitory effects were different by the existence of cumulus. Based on them it is suggested that the cumulus modulates the role of cGMP in GV arrest.

• Clinical and Experimental Reproductive Medicine
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• 제1권1호
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• pp.49-54
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• 1974

In the present studies, effect of progesterone on the germinal vesicle break-down of the mouse oocytes cultured in the micro tube was investigated. The results obtained are as follows: As dose of progesterone in the medium rose, accordingly the break-down of the germinal vesicle was suppressed. It was found that $ED_{50}$ was 15.7 ${\mu}g$/ml, and $ED_{90}$ 60.7 ${\mu}g$/ml of progesterone. The dose suppressing the oocyte maturation was apparently higher than that on the rabbit or on the mouse embryonal development. The inhibiting effect of progesterone on the GVBD was reversible. The germinal vesicle of the oocytes were broken down immediately in the medium upon removal of the hormone. Progesterone stops meiosis at any stage upon administration, while dbe AMP or theophylline supresses only the break-down of the nuclear membrane. Recovering of the meiotic division of the oocytes once exposed to progesterone was delayed a little. The inhibiting action of progesterone was not altered by adding more pyruvate or in the presence of higher concentration of the mineral ions in the culture medium.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.61-61
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• 2003

We have investigated the novel function of tissue transglutaminase (tTG) in the germinal vesicle breakdown (GVBD) of mouse oocyte. tTG was identified in ooplasm and germinal vesicle by immunostaining assay. Spontaneous maturation of the oocytes elevated in situ activity of tTG by over 2.5 fold at 3 hr, which was determined by a confocal microscopic assay. However, incubation with monodansylcadaverine (MDC), a tTG inhibitor, blocked the activation of tTG. The possible role of tTG in GVBD was investigated by the use of two tTG inhibitors, MDC and cystamine. MDC largely inhibited the GVBD by a concentration dependent manner. GV-stage oocytes were matured to the GVBD stage by 78% at 3 hr in BWW culture medium. However, in the oocytes incubated with MDC for 3 hr, the GVBD rates were 43 and 11% by 50 and 100 mM, respectively. MDC also blocked the entry of 70 kDa TRITC-dextran from the ooplasm to the compartment of germinal vesicle, indicating a possible inhibition of nuclear pore disassembly by MDC. The role of tTG in GVBD was further investigated by microinjection with cystamine. The control oocytes, injected with DPBS, showed about 80 % of GVBD at 3 hr. But the oocytes injected with cystamine showed 15% of GVBD at 3 hr and a little higher rate at 6 hr. In addition, the inhibition of GVBD maturation by MDC was reversible by washing. These results suggested that tTG was involved in the early event of mouse oocyte maturation

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2002년도 춘계학술발표대회 발표논문초록집
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• pp.72-72
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• 2002

Oocytes maturation, characterized by germinal vesicle (GV) breakdown, formation of the first meiotic spindle, expulsion of the first polar body and arrest in metaphase of second meiotic division (MII), occurs in preovulatory follicles in response to the surge of gonadotropin and leads to an ovulated oocyte in vivo. However, meiotic resumption in vitro occurs spontaneously following removal of cumulus-oocytes complexes (COCs) from the follicle. (omitted)

• 한국동물학회지
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• 제36권1호
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• pp.77-83
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• 1993

난모세포성숙기 (peripheral germinal vesicle stage)의 무지개송어(Oncorhynchus mykiss)를 대상으로 방사성 표지 전구체(3H-pregnenolone, 3H-l7$\alpha$-hydroxyprogesterone 그리고 3H-androstenedione)를 이용하여 유 nitro에서 관찰한 협막세포층의 스테로이드 주 대사 경로는 다음과 같으며, pregnenolone -) 17a-hydroxypregnenolone$\longrightarrow$ 17u-hydroxyprogesterone $\longrightarrow$ androstenedione $\longrightarrow$ testosterone 이는 $\Delta$5-스테로이드 경로의 존재가능성을 지적하고 있다.

• 한국가축번식학회지
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• 제20권3호
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• pp.343-351
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• 1996

본 연구의 목적은 돼지난자의 체외성숙, 수정 및 단위발생시 일어나는 표층과립의 분포를 살펴보고, 그것들의 역할을 규명해 보고자 실시하였다. 난자의 표층과립은 형광염색을 실시한 후 laser scanning confocal microscope를 이용하여 관찰하거나 transmission electron microscope를 사용하여 관찰하였다. Germinal vesicle 단계의 돼지난자에서는 표층과립은 난자피질에 비교적 두꺼운 형태로 발견되었는데, germinal vesicle breakdown이 일어난 직후 피질 부근으로 표층과립의 움직임이 관찰되었다. Microfilaments의 중합화를 방해하는 cytochalasin B를 처리하였을 때 표층과립의 움직임은 관찰되지 않았다. 무 처리군의 수정 및 단위발생을 유도한 난자에서는 표층과립 내용물들이 위란강내에 균질하게 관찰되었으나, cytochalasin B를 처리한 난자에서는 비정상적인 cortical granule의 움직임을 관장하고 이러한 움직임이 수정시 다정자 침입을 막고 표층과립 반응에 영향을 미치는 것으로 사료된다.

• 한국발생생물학회지:발생과생식
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• 제17권2호
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• pp.141-147
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• 2013

Keeping the intact germinal vesicle (GV) is essential for maintaining the capacity of mammals including human. It is maintained by very complex procedures along with folliculogenesis and is a critical step for getting competent oocyte. So far, a few mechanisms involved in folliculogenesis are known but GV arrest mechanisms are largely unrevealed. Cyclic AMP, a adenosine derived substance, have been used as inhibitor of germinal vesicle breakdown as a putative oocyte maturation inhibitor. In this study, we examined the potency of adenosine as GV maintainer and a possible signaling mediator for that. A1, A2b, and A3 were detected in cumulus cells of cumulus enclosed-oocyte (CEO). Intact of germinal vesicle was not kept like in follicle but the spontaneous maturation was inhibited by exogenous adenosine. It is inhibited with concentration dependent manners. Intracellular calcium level of cumulus was extensively increased after adenosine treatment. Based on these results it is suggested that one of the pathway for GV arrest by adenosine and its receptors is calcium mediated signaling pathway in CEO.

• Reproductive and Developmental Biology
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• 제34권3호
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• pp.169-173
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• 2010

Correlations between cumulus cells and germinal vesicle (GV) chromatin configuration were examined in porcine oocytes. Cumulus-oocyte complexes (COCs) were collected from 2~6 mm follicles and divided into three categories according to cumulus cell morphology. "A" group was compacted COCs with more than three cumulus cell layers. "B" group was COCs with less cumulus cell layers than "A" group. "C" group was COCs with one or less layer of cumulus cells. Cumulus cells were removed 0.1% hyaluronidase, and denuded oocytes were stained with Hoechst 33342. GV chromatin configuration was classified into GV-Con and GV-Dis. GV-Con meant that a nucleus was surrounded by condensed chromatin in a ring. GV-Dis meant that filamentous chromatin clumps were distributed in nucleus. The proportion (80.2%) of GV-Con in "A" group was significantly higher than "B" (62.0%) or "C" (44.9%). The proportion (55.1%) of GV-Dis in "C" group was significantly higher than "A" (19.8%) or "B" (38.0%). The meiotic competence of COCs was examined after 44 h culture. The proportion (90.0%) of oocytes reaching to metaphase II (M-II) in "A" group was significantly higher than "B" (76.5%) or "C" (45.5%). In conclusion, oocytes with good quality cumulus cell layers are synchronized early GV stage, and early GV stage is important for meiotic competence in pigs.

• Reproductive and Developmental Biology
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• 제29권4호
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• pp.223-227
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• 2005

In vitro maturation of porcine immature cumulus-enclosed oocytes can be enhanced by co-incubation with spermatozoa even before fertilization. The aim of this study was to determine whether the addition of spermatozoa into the culture medium can stimulate the meiosis resumption of porcine cumulus-enclosed oocytes arrested at germinal vesicle (GV). Cumulus-enclosed oocytes (CEOs) were collected from follicles of 3 to 5mm diameter. Porcine CEOs were cultured in tissue culture medium containing various meiosis inhibitors and spermatozoa. Oocytes were examined for evidence of GV and GV breakdown after 24 h culture. After 24 h culture $43.8\%$ of oocytes cultured in only TCM 199 remained at GV stage whereas $56.2\%$ of oocytes were able to resume meiosis. When porcine CEOs were cultured in the medium with meiosis inhibitor such as, dibutyryl cAMP (dbcAMP) and forskolin (Fo), more than $90\%$ of oocytes were not able to resume meiosis. However, co-culture of porcine CEOs with spermatozoa was able to overcome the inhibitory effect of dbcAMP and Fo. Irrespective of the presence of 3-isobutyl-1-methylxanthine (IBMX), no difference was observed in the proportion of oocyte reached germinal vesicle breakdown (GVBD). The present study suggests that dbcAMP and Fo prevent the spontaneous maturation of competent oocyte in culture after isolation from follicles and that mammalian spermatozoa contain a substance(s) that improves meiosis resumption in vitro of porcine cumulus-enclosed oocytes.

• 한국수정란이식학회지
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• 제7권1호
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• pp.41-47
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• 1992

1. In vitro system, LR and FSR accelerated and facilitated meiotic progression, and LH selectively improved cytoplasmic maturation which is required to promote the formation of a male pronucleus. 2. Caffeine (2mM) in the fetilization medium was required not only for inducing zona penetrating ability of boar also for developing to the male pronucleus of the penetrat- ing spermatozoa in vitro. 3. The germinal vesicle (GV)stage was observed for the first 17.6 hr;germinal vesicle break-down (GVBD)stage between 17.6~26.4 hr ;metaphase I (M-I)from 26.4 - 30. 9hr;anaphase I(A-I)ranged from 30. 9~33.4hr;telophase I(T-I) at 33.4~34.4hr; and metaphase II(M-II) at 34.4-48hr. 4. The addition of 10%(v /v) pig follicular fluid (pFF) to maturation media significantly increased the rate of nuclear maturation of pig oocytes (p<0.01), whereas the rate of nuclear maturation of pig oocytes among three different media did not differ. 5. The presence of a primary culture of POEC promotes in vitro development of early cleavage stage pig embryos.