• Animal cells and systems
• /
• 제11권1호
• /
• pp.1-8
• /
• 2007

Recently, we have shown that some endocrine disruptors, heavy metals, organotins and azoles suppressed steroidogenic enzymes such as P450 side-chain cleavage enzyme (P450scc) and aromatase in bullfrog ovarian follicles. In the present study, by using an amphibian ovarian follicle culture system, we examined the effects of these endocrine disruptors on maturation and ovulation of oocytes from Rana dybowskii in vitro. Ovarian fragments or isolated follicles were cultured for 24 h in a medium containing frog pituitary homogenate (FPH) or progesterone ($P_{4}$) with or without endocrine disruptors, and oocyte maturation (germinal vesicle breakdown, GVBD) and ovulation were examined. Among the organotins, tributyltin (TBT) strongly inhibited both FPH-and $P_{4}-induced$ oocyte maturation ($ED_{50}$:0.6 and 0.7 ${\mu}M$, respectively); however, tetrabutyltin (TTBT) and dibutyltin (DBT) showed only partial suppression, while monobutyltin (MBT) showed no inhibitory effect. All of the organotins suppressed $P_{4}-induced$ oocyte ovulation very effectively at a low concentration, and TBT and DBT exerted an inhibitory effect on FPH-induced ovulation. Among the heavy metals, mercury (Hg), cadmium (Cd) and cobalt (Co) were very effective in inhibiting FPH-induced oocyte maturation and ovulation, while lead (Pb), arsenite (As) and zinc (Zn) were less effective. However, all of the heavy metals suppressed FPH-induced oocyte ovulation at a high dose ($100{\mu}M$). Among the azoles, itraconazole (ICZ), ketoconazole (KCZ) and clotrimazole (CTZ) effectively inhibited FPH-induced oocyte maturation and ovulation, while econazole (ECZ), miconazole (MCZ) and fluconazole (FCZ) were considerably less effective. These results demonstrated that the abovementioned endocrine disruptors exhibited differential effects on oocyte maturation and ovulation in amphibian follicles and that the frog ovarian culture system could be used as an effective experimental tool to screen and evaluate the toxicity of various endocrine disruptors in vitro.

• 한국수산과학회지
• /
• 제50권1호
• /
• pp.41-47
• /
• 2017

Perhaps the most common type of reproductive dysfunction in captive fish is failure of females to undergo final oocyte maturation and thus to ovulate and spawn. The success of aquaculture could therefore be improved by developing techniques to enhance natural spawning, artificial maturation, and/or to induce ovulation in farmed fish. This study aimed to investigate the effects of prostaglandin $E_2$ ($PGE_2$) and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) on in vitro oocyte maturation (germinal vesicle breakdown, GVBD) and ovulation in the marine fish Chasmichthys dolichognathus. Post-vitellogenic follicles (0.80-0.94 mm diameter oocytes) were incubated with $PGE_2$ or $PGF_{2{\alpha}}$ at concentrations of 5, 50, or 500 ng/mL for 24 hours. A significant increase in GVBD was seen in 0.84 mm and 0.94 mm oocytes incubated with 50 ng/mL $PGE_2$ compared with the control. There was no significant increase in GVBD in any of the other experimental conditions (5 or 500 ng/mL $PGE_2$ or 5, 50, or 500 ng/mL $PGF_{2{\alpha}}$). Neither of the prostaglandins induced ovulation at the concentrations tested.These results suggest that GVBD was induced by incubation with 50 ng/mL $PGE_2$.

• 한국수산과학회지
• /
• 제34권6호
• /
• pp.584-587
• /
• 2001

성숙 시기의 넙치 (Paralichthys olivaceus) 어미를 대상으로 난 모세포의 GVBD와 배란유도과정에 TBT/TPhT와 Aroclor 1254의 저해효과를 조사한 결과, TBT (또는 TPhT)와 Aroclor 1254모두 GVBD 과정과 HCG로 전처리한 배란유도 과정에 저해효과를 보였으며, 난모세포의 반응은 Aroclor 1254보다는 TBT에 좀 더 민감한 것으로 나타났다. TBT의 처리 농도별 차이는 TBT 0.1과 1 ppm에서 가장 낮은 GVBD 유도율을 보였으나 $0.0001\~1\;ppm$ 사이에 유의한 차이는 관찰할 수 없었다 TBT의 배란저해 효과는 HCG 처리 구에 비해 HCG+TBT의 모든 실험구 (0.01, 0.1, 1 ppm)에서 뚜렷하게 나타났으며, TBT 처리구 중 가장 높은 농도인 HCG+TBT 1 ppm에서 가장 낮은 배란율을 보였다. 넙치의 GVBD와 배란과정을 유기주석화합물 (TBT, TPhT)이 방해함으로써 이 시기의 주요 호르몬인 progestogens 작용이 저해되는 것으로 생각되며, 앞으로 난소발달 단계별로 세분화하여 그 저해 작용 메커니즘에 대한 실험이 요구된다.

• 한국수산과학회지
• /
• 제30권2호
• /
• pp.203-210
• /
• 1997

동자개 난모세포의 성숙과 배란에 있어 스테로이드와 HCG(human chorionic gonadotropin)의 효과에 대한 실험이 in vitro에서 이루어졌으며, 난모세포들은 $17\alpha,\;20\alpha-dihydroxy4-pregnen-3-one\;(17\alpha\;20\alpha\;OHP),\;17\alpha-hydroxyprogesterone\;(17\alpha\;OHP),\;progesterone\;(P_4),\;estradiol-17{\alpha}E_2)$ 과 HCG가 첨가된 Leibovitz L15 배지에서 성숙되어졌다. 60시간 배양후에 난모세포의 성숙능력은 난핵포붕괴(germinal vesicle breakdown, GVBD) 비율에 의해 평가되었다. GVBD 비율은 $17\alpha\;20\alpha\;OHP,\;17\alpha\;OHP,\;P_4$ 그리고 HCG의 첨가에 의해 유의하게 (P<0.05) 증가하였으며, 그 중 $17\alpha\;20\alpha\;OHP$ HCG에서 가장 높은 GVBD 비율을 보였다. 난모세포들 $17\alpha\;20\alpha\;OHP,\;17\alpha\;OHP,\;P_4$가 $10\~1,000ng/ml$포함된 배지에서 16시간 배양한 결과, $17\alpha\;20\alpha\;OHP\;10\~100ng/m1(65\%)$의 GVBD 비율은 $17\alpha\;20\alpha\;OHP(40\%)$와 $P_4(35\%)$에서 보다 나은 효과를 보였다. GVBD유도에 대한 효과는 $17\alpha\;20\alpha\;OHP$에서 $10\~100\;ng/ml$배지, HCG를 첨가하여 60시간 배양한 배란유도 실험에서 $17\alpha\;20\alpha\;OHP\;10\~100ng/ml$에서, HCG는 $50\~500IU/ml$의 배지에서 배란율이 유의하게 증가하였다. 그러나 $17\alpha\;20\alpha\;OHP\;1,000ng/m1$와 HCG 5IU/ml의 배지에서는 대조구의 배란율과 차이를 보이지 않았다. 이러한 결과로 $E_2$를 제외한 스테로이드와 HCG는 동자개의 난모세포 성숙과 배란을 in vitro에서 유도할 수 있으며, $17\alpha\;20\alpha\;OHP$와 HCG는 다른 스테로이드에 비해 높은 율의 난모세포 성숙과 배란을 유도하였다.

• Molecules and Cells
• /
• 제40권8호
• /
• pp.558-566
• /
• 2017

Regular monitoring on experimental animal management found the fluctuation of ART outcome, which showed a necessity to explore whether superovulation treatment is responsible for such unexpected outcome. This study was subsequently conducted to examine whether superovulation treatment can preserve ultrastructural integrity and developmental competence of oocytes following oocyte activation and embryo culture. A randomized study using mouse model was designed and in vitro development (experiment 1), ultrastructural morphology (experiment 2) and functional integrity of the oocytes (experiment 3) retrieved after PMSG/hCG injection (superovulation group) or not (natural ovulation; control group) were evaluated. In experiment 1, more oocytes were retrieved following superovulation than following natural ovulation, but natural ovulation yielded higher (p < 0.0563) maturation rate than superovulation. The capacity of mature oocytes to form pronucleus and to develop into blastocysts in vitro was similar. In experiment 2, a notable (p < 0.0186) increase in mitochondrial deformity, characterized by the formation of vacuolated mitochondria, was detected in the superovulation group. Multivesicular body formation was also increased, whereas early endosome formation was significantly decreased. No obvious changes in other microorganelles, however, were detected, which included the formation and distribution of mitochondria, cortical granules, microvilli, and smooth and rough endoplasmic reticulum. In experiment 3, significant decreases in mitochondrial activity, ATP production and dextran uptake were detected in the superovulation group. In conclusion, superovulation treatment may change both maturational status and functional and ultrastuctural integrity of oocytes. Superovulation effect on preimplantation development can be discussed.

• Asian-Australasian Journal of Animal Sciences
• /
• 제14권2호
• /
• pp.174-183
• /
• 2001

During the rapid phase of gonadal development of the freshwater teleost, the catfish (Silurus asotus), the influence of hCG upon the inducement of final oocyte maturation and spawning was investigated electrophoretically and ultrastructurally. The electrophoretic patterns obtained were different in the presence and absence of some of the major or minor zones, because of the hormone level in catfish. The vitellogenin of hormone-treated fish was stained more intensively than that of sham-treated fish. These proteins showed some minor or main bands of egg extracts which migrated at positions corresponding to molecular weights of approximately 90,000. However, the thickness of electrophoretic band in molecular weight for hCG-treated fish was slightly lower than that for saline control. It seemed the plasma protein with molecular weight of approximately 45,000 in hCG-treated fish disappeared. In contrast to the control fish, the ovaries in the catfish treated with hCG shows a marked ultrastructural change under the electron microscope. No dilated profiles were seen in the granulosa cells of the mature oocyte before ovulation. After germinal vesicle breakdown (GVBD), the zona radiata interna (ZRI) becomes more compact, and there is a loss of all the processes from the pore canals. There is a wide space between the vitelline membrane and zona radiata. Also, during final maturation, the microvillar processes from the oocyte are seen no longer to penetrate deeply into the extracellular spaces of the overlying granulosa cells, and the reticulate patterns of the zona radiata interna becomes occluded, giving the zona radiata a more solid appearance. It has been possible to initiate 100% oocyte maturation in yolk granules and follicles in vivo by treatment with hCG and a high water temperature ($27^{\circ}C$). In hCG-treated fish, the percentages of successful artificial fertilization and hatching were maximal at 15 h after a single injection. It seems clear that a long acting preparation containing hCG can be successfully used in prespawning fish to advance the final events of gonadal maturation and initiate spawning. Further studies are necessary to evaluate the potential of hCG to either stimulate or inhibit the reproductive development of fish at other stages of the seasonal reproductive cycle.

• Reproductive and Developmental Biology
• /
• 제38권2호
• /
• pp.63-70
• /
• 2014

Plasminogen activators (PAs) are serine proteases that convert plasminogen to plasmin. Two type of PAs are urokinase-type PA (uPA) and tissue-type PA (tPA). Plasminogen is present in most extracellular fluids. PAs play in various reproductive processes including implantation, ovulation and fertilization. In the spermatozoa, PAs and PAIs play a role in sperm motility and fertilization. PAs in the sertoli cell are stimulated spermatozoa maturation and sperm activation through the phospholipase A2. The oocyte maturation is the process for fertilization and implantation. PAs in cumulus-oocyte complexes (COCs) are related to oocyte maturation by protein kinase A and C. In the ovulatory process, PAs activity are changed and it are related to reducing the tensile strength of ovarian follicle wall. The uterine environment is important for reproduction and the uterus undergo tissue remodeling. In the uterus and oviduct of mammals, expression and activity of PAs are changed during estrous cycle. Thus, expression and activity of PAs are concerned to many reproductive functions. Therefore, PAs seem to important factor of regulator in reproductive events.

• 한국양식학회지
• /
• 제21권2호
• /
• pp.96-101
• /
• 2008

능성어 암컷의 난모세포 발달에 따른 성숙 및 배란유도를 위하여 제주도 연안에서 채집하여 사육중인 능성어 51마리(전장 $69.1{\pm}1.0cm$, 체중 $5.8{\pm}0.3kg$)를 대상으로 암컷의 생식소 발달을 cannulation으로 조사하였다. 난황구기 단계 이상 난모세포(난경 $300{\sim}500{\mu}m$)를 가진 어미를 대상으로 HCG 500 IU/kg BW로 주사하였다. HCG 처리 후 난경변화는 24시간째에 $300{\sim}700{\mu}m$, 48시간째에는 $800{\mu}m$ 이상이 $91.3{\sim}98.8%(95.1{\pm}3.7%)$이었다. HCG 처리 실험구에서는 실험어 8마리 중 7마리가 배란되었고, 총 배란된 알 2,480 mL이었으며, 이중 부상란은 1,360 mL이었다. 수정률과 부화율은 각각 $56.2{\sim}94.9%(77.8{\pm}2.9%),\;70.0{\sim}97.7%(92.2{\pm}2.1%)$이었다. 이들 결과들은 HCG 500 IU/kg BW 농도로 처리했을 때 난황구기 난모세포를 가진 능성어 암컷의 성숙 및 배란에 효과가 있을 것으로 사료된다.

• Clinical and Experimental Reproductive Medicine
• /
• 제14권1호
• /
• pp.7-17
• /
• 1987

It appears that a major determinant of the success of in vitro fertilization is the selection of the optimal follicle containing an oocyte capable of being fertilized and producing a normal pregnancy. However, the hormonal basis of oocyte maturation is not well substantiated by the as yet available informations. It has been suggested that prolactin(PRL) may stimulate the formation of an oocyte maturation inhibitor and thus inhibit the maturation of oocyte. During the hyperstimulated menstrual cycles serum estradiol($E_2$) levels are markedly elevated, and it seems justified to assume that serum prolactin levels may be elevated since estrogens are potent stimulators of prolactin secretion. This study was carried out to ascertain the effect of the elevated serum estradiol levels on the serum prolactin levels in women undergoing ovarian hyperstimulation with either hMG and/or clomiphene citrate. Serum estradiol and prolactin profiles were measured from third menatrual cycle day to ovulation or ovum aspiration day in 11 normal menstruating women and 30 women who underwent an in vitro fertilization procedure with ovarian hyperstimulation by hMG, clomiphene citrate/hMG, clomiphene citrate. Ovum aspiration was performed 36 hours after hCG administration. The day of ovum aspiration or ovulation was designated Day 0. Serum estradiol levels increased progressively during the follicular phase and this rise peaked on Day-1 at a mean concentration of 1,204${\pm}$189.0pg/ml in Group II(hMG), 1,194${\pm}$167.9pg/ml in Group III(clomiphene citrate/hMG), 1,035${\pm}$195.1pg/ml in Group IV(clomiphene citrate) respectively and on Day -2 of 336${\pm}$34.5pg/ml in Group I(normal control). The elevated estradiol levels fen rapidly after ovulation or ovum aspiration. Serum estradiol values of hyperstimulated groups(Group II, III, IV) were significantly higher than that of control group(Group I) from Day -6 to Day +1, but there was no significant difference of estradiol values among the hyperstimulated groups. Serum prolactin levels increased and peaked on Day +1 at a mean concentration of 60.8${\pm}$14.4ng/ml in Group II, 34.2${\pm}$7.0ng/ml in Group III, 30.1${\pm}$5.7ng/ml in Group IV respectively, but no significant elevation was observed in Group I. Levels of estradiol and prolactin can be positively and significantly correlated in the hyperstimulated groups. However, the increase of serum prolactin levels in hMG group was significantly higher than those in clomiphene citrate/hMG or clomiphene citrate group.

• Asian-Australasian Journal of Animal Sciences
• /
• 제29권8호
• /
• pp.1065-1074
• /
• 2016

Growth factors play an important role during early ovarian development and folliculogenesis, since they regulate the migration of germ cells to the gonadal ridge. They also act on follicle recruitment, proliferation/atresia of granulosa cells and theca, steroidogenesis, oocyte maturation, ovulation and luteinization. Among the growth factors, the growth differentiation factor 9 (GDF9) and the bone morphogenetic protein 15 (BMP15), belong to the transforming growth factor beta (TGF-${\beta}$) superfamily, have been implicated as essential for follicular development. The GDF9 and BMP15 participate in the evolution of the primordial follicle to primary follicle and play an important role in the later stages of follicular development and maturation, increasing the steroidogenic acute regulatory protein expression, plasminogen activator and luteinizing hormone receptor (LHR). These factors are also involved in the interconnections between the oocyte and surrounding cumulus cells, where they regulate absorption of amino acids, glycolysis and biosynthesis of cholesterol cumulus cells. Even though the mode of action has not been fully established, in vitro observations indicate that the factors GDF9 and BMP15 stimulate the growth of ovarian follicles and proliferation of cumulus cells through the induction of mitosis in cells and granulosa and theca expression of genes linked to follicular maturation. Thus, seeking greater understanding of the action of these growth factors on the development of oocytes, the role of GDF9 and BMP15 in ovarian function is summarized in this brief review.