• Journal of Embryo Transfer
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• v.11 no.2
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• pp.179-191
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• 1996

In-vitro culture has provided new inforrnation on mechanisms of oocytes rnaturation and results obtained in vitro have led to new questions. In porcine, follicular and oocyte size have the crucial importance for the oocytes maturation. The addition of hormones to the culture medium was found to accelerate and facilitate meiotic maturation. The presence of some factors in serum trigger the resumption of meiosis and support the maturation of oocytes in vitro. The maturation rate of porcine oocytes was also increased by supplementation of porcine follicular fluid to the culture medium. The growth factors can stimulate nuclear maturation and enhances cytoplasnic maturation of oocytes by interaction with gonadotropins. The maturation-promoting factor brings about GVBD and the subsequent maturational events in oocytes. However, cAMP can block the spontaneous meiotic maturation of oocytes in culture. The understanding of these influences is a prerequisite to enhancing in vitro maturation of porcine oocytes.

• Korean Journal of Animal Reproduction
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• v.21 no.1
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• pp.53-59
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• 1997

This study was conducted to investigate the effect of hormones on in vitro maturation of porcine follicular oocytes. The results obtained were as follows : 1. The maturation rates of oocytes cultured in medium containing FSH 1, 10, 50 and 100$\mu\textrm{g}$/ml were 44.6, 58.5, 42.6 and 37.9%, respectively. And those were no difference to maturation rates among the medium containing FSH. However, the maturation rate(13.7%) of oocytes cultured without FSH was significantly(P<0.05) lower than those of oocytes cultured with FSH. 2. The maturation rates of oocytes cultured in medium containing hCG 0, 1, 10, 50 and 100IU/ml were 12.2, 11.9, 17.9, 21.9 and 45.6%, respectively. The maturation rate of oocytes cultured with 100IU/ml hCG was significantly(P<0.05) higher than those of oocytes cultured with 0~50IU/ml hCG concentrations. 3. The maturation rates of oocytes cultured in medium containing E2 0, 1, 10, 50 and 100$\mu\textrm{g}$/ml were 13.7, 10.5, 14.9, 11.4 and 5.9%, respectively. There were no differences to maturation rates among the E2 concentrations. 4. The FSH＋hCG treatment was the highest maturation rate in medium containing different combination of FSH, hCG and E2.

• Korean Journal of Animal Reproduction
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• v.19 no.4
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• pp.251-258
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• 1996

These studies were carried out to investigate the effect of gonadotropins (GTH), fetal calf serum (FCS), porcine follicular fluid (pFF) and FCS and pFF fractions obtained by the gel filtration on in vitro maturation of porcine follicular fluid. When the oocytes were cultured in TCM-199, the maturation rate was higher in pFF than in FCS in both with or without GTH and in pFF the maturation rate was higher in with GTH than in without GTH. In case of without GTH, pFF increased maturation rates in TCM-199, but not in Whitten's medium (WM). When the oocytes were cultured in WM supplemented with FCS fractions, the maturation rate(51.6%) of oocytes was significantly (P<0.05) higher in fraction B (about 30∼70 kDa) than in control, FCS and other fractions. When oocytes were cultured in WM supplemented with pFF fractions, fractions B (about 30∼70 kDa) and D (about 1∼10 kDa) were significantly (P<0.05) higher than in control, pFF and other fractions. In conclusiion, the addition of gonadotropins into the maturation media was effective for oocyte maturation. The addition of pFF was more effective than addition of FCS for maturation of porcine oocytes in vitro. And fraction B from FCS and fractions B and D from pFF was effective for oocyte maturation.

• Reproductive and Developmental Biology
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• v.39 no.2
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• pp.37-41
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• 2015

The oocyte undergoes various events during maturation and requires many substances for the maturation process. Various intracellular organelles are also involved in maturation of the oocyte. During the process glucose is essential for nuclear and cytoplasmic maturation, and adenosine triphosphate is needed for reorganization of the organelles and cytoskeleton. If mitochondrial function is lost, several developmental defects in meiotic chromosome segregation and maturation cause fertilization failure. The endoplasmic reticulum, a store for $Ca^{2+}$, releases $Ca^{2+}$ into the cytoplasm in response to various cellular signaling molecules. This event stimulates secretion of hormones, growth factors and antioxidants in oocyte during maturation. Also, oocyte nuclear maturation is stimulated by growth factors such as epidermal growth factor. This review summarizes roles of organelles with focus on the Golgi apparatus during maturation in oocyte.

• Reproductive and Developmental Biology
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• v.30 no.2
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• pp.115-118
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• 2006

Cyclin B1 is known to reflect the M-phase promoting factor (MPF), a universal regulator of G2/M-phase transition, activity during the process of oocytes maturation. To investigate whether culture condition affects the maturation rate and the expression of cyclin B1 protein, bovine immature oocytes are stimulated and cultured according to the following protocols: Experiment 1: denuded oocytes (denude) only, COC only, denuded oocytes+granulosa cells (denude+GCs) and COC+GCs; Experiment 2: no-activation (control), 7% ethanol for 5 min and $10{\mu}l/ml$ ionomycin for 5 min at immediately before maturation. The maturation rates of denude and no-activation group were significantly lower in both experiments (P<0.05), respectively. Co-culture or stimulation method in bovine immature oocytes culture increases the cyclin B1 expression significantly in both experiments (P<0.05). Based on these results, culture condition affects the maturation rate and the expression of cyclin B1 protein during the first meiotic maturation in bovine immature oocytes.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.183-188
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• 2021

In vitro maturation (IVM) of oocytes is the procedure where the immature oocytes are cultivated in a laboratory until they are mature. Since IVM oocytes generally have low developmental competence as compared to those matured in vivo, development of an optimal IVM culture system by fine-tuning culture conditions is crucial to maintain high quality. In-depth knowledge and a deep understanding of the in vivo physiology of oocyte maturation are pre-requisites to accomplish this. Within ovarian follicles, various signaling pathways that drive oocyte development and maturation regulate interaction between oocytes and surrounding somatic cells. This review discusses the sonic hedgehog (SHH) signaling pathway, which has been demonstrated to be intimately involved in folliculogenesis and oocyte maturation. Advances in elucidating the role of the SHH signaling pathway in oocyte maturation will aid attempts to improve the current inferior in vitro oocyte maturation system.

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.188-195
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• 1991

The effect of lanthanum ion (La3 +), which is associated with the mobilization of internal calcium, on the regulation of oocyte maturation was investigated with Rana dybowskii follicles. Follicular oocytes matured (germinal vesicle breakdown, GVBD) dose dependently when they were exposed to La3+ (O.O1-1.O mM) and the maturation occurred in 9-12 hours after the la3+(0.33 mM) stimulation. lanthanum also accelerated the onset of maturation of the lollicular oocytes exhibiting spontaneous maturation. Three hours of exposure to La3+ was enough to induce the maturation. The La3 + -induced maturation was not associated with progesterone production by follicle cells, and the maturation was inhibited by forskolin (9 $\mu$ M), and cyclobeximide (0.01 - 1.0 - $\mu$g/2 ml) in the medium. The La3+ and hormone stimulated maturation showed the same patterns of protein phosphorylation and dephosphorylation during the maturation. The data suggest that the oocyte maturation by La3+ stimulation is very similar to that by progesterone. Thus, it seems that internal mobilization of Ca2+ plays a key role in the initiation of oocyte maturation in amphibia.

• Korean Journal of Animal Reproduction
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• v.21 no.4
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• pp.381-387
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• 1997

This study was conducted to investigate the effects of fetal bovine serum(FBS), calf serum(CS) and human serum(HS) on in vitro maturation of porcine follicular oocytes. The results obtained were summarized as follows : 1. The maturation rates of oocytes cultured in medium containing FBS 5, 10, 20 and 30% were 47.0, 63.5, 48.4 and 43.2%, respectively. There were significantly higher than those of non-treated group(25.3%). And the highest maturation rate was the 10% treatment. 2. The maturation rates of oocytes cultured in medium containing CS 5, 10, 20 and 30% were 55.2, 56.6, 59.4 and 46.5%, respectively. There were significantly higher than those of non-treated group(25.3%). And the highest maturation rate was the 20% treatment. 3. The maturation rates of oocytes cultured in medium containing HS 5, 10, 20 and 30% were 74.5, 78.2, 73.1 and 68.6%, respectively. There were significantly higher than those of non-treated group(29.6%). And the highest maturation rate was the 10% treatment.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.117-122
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• 1997

The aim of this study was to investigate the effect of the follicular culture from which the oocytes originate on their subsequent in vitro maturation ability. Ovarian follicles were isolated and cultured according to size(1~2mm, 2~6mm and 6~8mm) for 42~44 h. The rates of germinal vesicle breakdown(GVBD) in each groups were 87%(65/75), 82%(80/97) and 89%(47/53), but the oocytes maturation were su, pp.essed at anaphase-I stage. In spite of the adding porcine follicular fluid and/or hormones in maturation medium, maturation ability of oocytes from follicle cultured for 21~22 h were inhibited. When oocytes from follicle cultured for 4 h at various temperature were incubated for 38~40 h, the rates of oocytes maturation from follicle cultured at 2$0^{\circ}C$(51%, 26/51) and 39$^{\circ}C$(54%, 26/48) were significant higher(P<0.05) than group cultured at 4$^{\circ}C$(33%, 19/58). On the other hand, the GVBD were stared 2 h after culture of follicle of oocytes. To summairze, oocytes maturation by follicular culture were inhibited at anaphase-I stage in porcine. When the follicle cultured for 4 h, maturation were completed to metaphase-II stage. However, rates of GVBD in oocytes from follicular culture were higher than oocytes cultured in medium.

• Korean Journal of Animal Reproduction
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• v.20 no.3
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• pp.289-297
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• 1996

This study was conducted to investigate the effects of maturaton medium and porcine follicular fluid on in vitro maturation of porcine follicular oocytes. The results obtained are as follows; 1. When the oocytes were cultured for 42 hours, the maturation rate was significantly (P<0.05) higher in TCM-HEPES(75.5%) than Ham's F-10(60.9%) and mKRB(60.7%) medium. The optimal medium for the maturation of porcine oocytes in vitro was the TCM-HEPES medium. 2. When the oocytes were cultured for 42 hours in TCM-HEPES medium with 10, 20 and 30% of porcine follicular fluid(pFF), the maturation rates of porcine oocytes were 69.1, 65.6 and 63.3%, respectively. The maturation rate(51.4%) of oocytes cultured without pFF was significantly(P<0.05) lower than that of oocytes cultured with pFF. 3. The maturation rates of porcine oocytes cultured for 42 hours in TCM-HEPEs medium with 3 different porcine follicular fluid treatments were 68.6%(centrifused), 72.3%(filtered) and 73.1%(heat treated), respectively. The maturation rate(49.4%) of control group without pFF treatment was significantly(P<0.05) lower than that of oocytes cultured with pFF treatment.