These experiments were carried out to investigate the effects of cumulus cells for in vitro fertilization and development of bovine follicular oocytes matured in vitro. The bovine ovaries were obtained at a slaughter house and the follicular oocytes surrounded by cumulus cells were collected by puncturing follicles with 2~6 mm of diameter. Bovine oocytes were matured in vitro for 24~26 hours in a CO2 incubator with 5% CO2 in air at 39$^{\circ}C$. The medium used for maturation was TCM-199 supplemented with hormones, pyruvate, FCS and antibiotics. Epididymal spermatozoa were capacitated by in vitro culture for 2~3 hours in BO solution containing BSA(5mg/ml) and caffeine(2.5mM). Insemination was made by introducing about 10~15 matured oocytes into the suspension of capacitated spermatozoa. Six hour after insemination the eggs were transferred to TCM-199 supplemented with FCS(10%) and HEPES(25mM), cultured for 7~8 days with 10~15 eggs/well in 4-well multidishes(Nunc Co.) forming cumulus cell monolayer. The results obtained in these experiments were summarized as follows ; 1. The majority of the follicular oocytes with compacted cumulus cells existed in GV stage while those with dispersed or denuded cumulus cells existed GVBD and M II stage. 2. After 24~26 hours maturation, the maturation rates of the follicular oocytes cultured in TCM-199 containing hormones were slightly higher than those of oocytes cultured in medium without hormones, and the frequency of cumulus compacted or denuded oocytes reaching M II stage cultured in medium containing hormones was 75.7% or 51.7%, respectively(P<0.05). 3. After 20 hours in vitro insemination, percentages of ova fertilized were 61.4% or 51.4%, respectively, for cumulus oophorus intacted or removed, and increased frequency of ova with both male and female pronuclei was found when cumuli were present(P<0.05). 4. The rates of embryos developed to 2-, 4-, 8-, 16-cell and morula or blastocyst stage after cocultured with cumulus cells were 65.0%, 45.3%, 34.7%, 28.0% and 22.7%, respectively. The results for momla or blastocyst stage were significantly higher than those of the embryos cultured in the basic medium(P<0.05).

This study was carried out in order to investigate effects of cryoprotectant concentration and equilibration time on survival of ultrarapidly frozen 2-cell mouse embryos. Mouse 2-cell embryos, following dehydration by exposure to DMSO and sucrose, were directly immersed into liquid nitrogen and thawed in 37$^{\circ}C$ water. Viability was defined by development rate to the blastocyst stage after in vitro culture for 72 hours. The results are summarized as follows ; 1. When 0.25M of sucrose was added into the freezing medium at various concentrations of DMSO and dilution medium, higher development rate of embryo was obtained in 3.0M DMSO concentrations (82.6%). However, when sucrose concentraitons of 0.25 and 0.5 M were added to the freezing medium with 3.0 M DMSO and dilution medium, development rate of embryos were 81.7% and 24.1%, respectively. 2. In the equilibration time at room temperature, higher development rate was attained after short period of time (2.5min) in 3.0 M DMSO＋0.25 M sucrose (85.9%). 3. The development rate of embryos at in vitro 2-cell, in vitro 2-cell, solution control and untreated control was 84.6%, 90.9%, 89.9%,, and 89.7%, respectively.

The present study was carried to investigate the development potential of bovine follicular oocytes matured and fertilized in vitro. Bovine oocytes matured in vitro were fertilized, cultured, and transfered to the rabbit oviduct for in vitro culture to evaluate the development potential. The rates of in vitro maturation, fertilization and polyspermy were 96%(355/369), 90%(320/355) and 15%(17/320), respectively. The percentage of oocytes cleaved after culture for 48 hours, to 2 cell, 3~4 cell, 6~8 cell stage were 17%(60/356), 21%(75/356) and 19%(67/356), respectively and overall cleavage rate was 57%(202/356). The rate of recovered embryos after 5 days in rabbit oviduct was 56%(80/142), and 21%(17/80) of recovered embryos developed over morula stage.

These studies were carried out to investigate the effects of fetal calf serum(FCS), estrous porcine serum(EPS), porcine follicular fluid(PFF), hormone and matured cumulus cell(MCC) on in vitro maturation and fertilization of porcine follicular oocytes. The ovaries and testes were obtianed from slaughtered Landrace sow and boars, respectively. The follicular oocytes surrounded with cumulus cells were recovered by aspirating follicular fluid from the visible follicles of diameter 3~5 mm and the semen were prepared from boar's epididymal cauda. The follicular oocytes were cultured in TCM-199 medium containing hormones, FCS, EPS, PFF and MCC for 48hrs. in a incubator with 5% CO2 in air at 36$^{\circ}C$ and then matured oocytes were again cultured for 18~20 hrs. with $1.5\times$106/ml motile capacitated sperm in the modified Tyroide solution containing 100$\mu\textrm{g}$/ml of heparin. The results obtained in these experiments were summarized as follows : 1. The maturation and fertilization rate of the follicular oocytes, cultured in the TCM-199 medium supplemented with 10% FCS and PMSG＋HCG were 55.6~64.5% and 33.3~37.1%, respectively. 2. The maturation and fertilization rate of the follicular oocytes cultured in the TCM-199 medium supplemented with 20% EPS and PMSG＋HCG were 50.0~55.0% and 30.3~33.3%, respectively. 3. The maturation rate(59.0~64.2%) and fertilization rate(34.8~39.3%) of follicular oocytes cultured in TCM-199 medium supplemented 20% FCS and 50% PFF were higher than those of follicular oocytes cultured in TCM-199 medium supplemented with 5%, 10% and 15% FCS and 10% and 50% PFF. 4. The maturation rate(60.0%) and fertilization rate(40.0%) of follicular oocytes cultured in TCM-199 medium supplemented with 20% FCS and granulosa cell (1$\times$106/ml) were significantly higher than those of fiollicular oocytes cultured in TCM-199 medium supplemented with 5%, 10% and 15% FCS and granulosa cell.

Eosin B의 사용에 의한 rat 난모세포의 생존성 및 발달가능성을 검사하였다. 염료는 Brinster's Medium for Ovum Culture puls glucose (BMOC)-2 medium ml당 eosin B 1.0mg을 함유하는 stock solution으로 준비하였다. 난모세포연구를 위하여 BMOC로 stock solution을 희석하여 만든 3가지의 염료농도들이 선택되었다 : 0.12mM, 0.60mM, 1.20mM. 난소세포들로부터 난모세포들을 채취하고, 보존기간 및 열 처리의 다양한 조건하에서 eosin B를 사용한 dye exclusion assay로 검사하였다. 생존한 난모세포는 eosin B를 배척하고, 사멸한 세포는 eosin B를 배척하지 않는 것으로 제시되었다.

The effect of preincubation on in vitro maturation and fertility were investigated using preovulatory oocytes with and without cumulus cells obtained from superovulated ouot-bred ICR mice. Oocytes were recovered from fully grown folicle at 10 hr after hCG administration. A part of oocytes recovered were treated with the solution of 0.1% hyaluronidase to remove cumulus cells. Both intact and treated oocytes were then incubated for 0 to 6hr in mT6 medium containing 0.3% BSA. After incubation for various times, a part of oocytes were subjected to the investigation of nuclear maturation and the remaining oocytes were used fro the induction of in vitro fertilization by adding them into medium containing capacitated mice epididymal spermatozoa. Above all, the percentage of preovulatory oocytes at the stage of metaphase II after preincubation for 0, 2, 4 and 6hr was 15.8, 36.4, 47.5 and 66.7%, respectively, suggesting the in vitro maturation of oocytes during their incubation. On the other hand, fertilizatin rate of oocytes preincubated for 0, 2, 4 and 6hr with and without cumulus cells were 41.0, 58.7, 68.7 and 75.6%, and 50.0, 45.1, 37.8 and 39.2%, respectively. No significant differences in fertilization rate between preovulatory oocytes preincubated for 6hr with cumulus cells and naturally ovulated were observed. These results suggest that cumulus cells take very important role in maturtion of oocytes in vitro. The precentage of preovulatory oocytes developed to 2-cell stage in vitro fertilization following preincubation for 0 to 6hr with and without cumulus cells ranged from 48.5 to 82.4% and 36.9 to 56.1%, respectively. Also, the rates of oocytes developed to blastocyst in vitro fertilization after preincubation for 0 to 6hr with and without cumulus cells were 28.1, 39.3, 42.5 and 44.0% and 12.5, 32.6, 24.4 and 15.5%, respectively. From these results, it could be said that fertility of preovulatory oocytes with cumulus cells could be improved to the level of that of naturally ovulated oocytes by adquate preincubation in vitro. Cumulus cells may, therefore, affect in vitro maturation, fertilization and following development of oocytes by influencing zona hardening.

To improve the freezing techniques of animal embryos using vitrification solution as a cryoprotectant rabbit embryos, by cell stages, dehydration temperature and dehydration temperature and dehydratin time, were frozen-thawed and cultured. Following are the main results obtained. 1. The damage rate of zona pellucida after thawing was higher(13.6%) when the cell stage of embryos was less than 4 cells than when the cell stage was 8~16 cell or morula. The damage rate was higher when the dehydration temperature was 4$^{\circ}C$ than -3$0^{\circ}C$ or -50~-8$0^{\circ}C$. The zona pellucida was damaged more when dehydrated for 5 min than when dehydrated for 10~15 min. 2. After being cultured for 72 hours, 5.3% of 4 cell(or less) embryos were developed to morula, while 86.4% of morula embryos were developed further. 3. More percentage of embryos(73.2%) was developed when dehydrated at -3$0^{\circ}C$ than when dehydrated at 4$^{\circ}C$ at -5$0^{\circ}C$~-8$0^{\circ}C$. 4. The hatching rate was higher when dehydrated for 5 min. When the embryos were dehydrated for 10~15 min and cultured for 24 hours, they were not even developed or development was not good in later stages.

Bovine oocytes obtained from follicles(2~5mm) of ovaries after slaughter were cultured in TCM 199 medium with 10~20% heat-inactivated estrus cow serum(ECS) for 25~27 hr, at 39$^{\circ}C$ under 5% CO2 in air. At the end of culture period, some oocytes were stained with 1% acetoorcein and examined for the evidence of oocyte maturation. The remainder were used to assess the potential of in vitro fertilization(IVF) with frozen-thawed spermatozoa and subsequent development in media with or without bovine oviduct epithelial cell (BOEC) co-culture. The results obtained were summarized as follows ; 1. The maturation rate of oocyte in vitro in TCM 199 medium with 15% ECS group(76.3) was superior to 10% ECS group(68.3%) and 20% ECS group(64.5%). 2. The IVF rates of oocytes matured in vitro, and formation rate of male and female pronuclei were 63.6%(77/121) and 93.5%(72/77), respectively. The incidence of polyspermy was very low(2.4%). 3. Of 73 oocytes fertilized in vitro and cultured in TCM 199 medium with 10% fetal calf serum for 7 days, 41(56.3%) were cleaved over 2-cell and only 1(2.4%) was developed beyond the 16-cell stage. 4. Of 76 oocytes co-cultured with BOEC, 58(76.3%) were cleavaged and 23(39.7%) were developed to morula and blastocyst stage. The results of this study indicate that co-culture with BOEC deserved a positive effect on the IVF oocyte development through the 16-cell block.

본 연구는 국립종축원과 경기도 남양주시의 개인 농장으로 부터 얻은 혈장과 유즙은 발정전 5일부터 시작 하여 2일 간격으호 30일간 채취하여 RIA와 CIA로 혈장, 전유 그리고 탈지유내의 progesterone을 측정 하여 발정주기중의 progesterone 농도 변화를 조사하였으며, 아울러 RIA와 대체할 수 있는 비방사성 면역 분석법인 CIA방법의 적용가능성을 조사하기 위하여 탈지유내 progesterone을 CIA와 RIA로 옹시에 측정하였던 바 다음과 같은 결과를 얻었다. 1. 혈장내 progesterone 수준은 발정전 8일까지 낮은 수준을 유지하다가 그후 급격히 증가하여 발정전 14일에 최고수준인 6.3ng/ml에 도달하였다. 그후 감소 하기 시작하여 발정전 16일에는 3.6ng/ml, 18일에는 1.5 ng/ml, 20일에는 2.2 ng/ml로서 최고수준을 나타냈다. 2. 임산우의 전유내 progesterone 농도는 발정일에 0.1 ng/ml에서 점차 증가하기 시작하여 발정후 10일 부터는 11ng/ml ~ 21ng/ml 까지의 높은 수준을 계속 유지하였다. 3 비임산우의 경우 전유내 progesterone농도는 발정일에 1.5 ng/ml 로서 낮은 수준을 나타냈으며 발정후 6일부터는 갑자기 증가하기 시작하며 발정후 16일까지 17.8~20.0 ng/ml까지의 높은 수준을 유지하다가 18일 이후부터는 1.4 ng/ml로서 낮은 수준을 유지하였다. 4. 탈지유내 progesterone수준은 임산우의 경우 발정개시때에 130-490pg/ml로서 낫은 수준을 유지하다가 발정 10일 이후에는 990-1650 pg/ml 까지의 높은 수준을 계속해서 유지했다. 5. 비임산부의 경우 탈지유내 progesterone 농도는 발정일에 160 pg/ml 로서 낮은 수준을 유지하다가발정후 8일부터 16일까지 1050-1300 pg/ml 까지 높은 수준을 오르내렸다 그후 탈지유내 progesterone수준을 240~450 pg/ml의 낮은 수준으로 나타났다. 6. 탈지유내 progesterone 농도를 CIA 와 RIA 방법으로 동시에 측정하여 상간관계플 조사하였던 바 좋은 상간관계(r=0.914)를 보였다.

This experiment was conducted to compare the fatty acid composition in the backfat and the levels of testosterone and androstenone in the serum of boars, barrows and gilts. The results obrained are summarized as follows : 1. The contents of palmitic acid and stearic acid in the backfat of barrows increased as their body weight increased and the levels of them were higher in barrows than in boars. However, the contents of oleic acid and linoleic acid were lower in barrows than in boars. 2. The levels of testosterone in boars at 70, 90 and 110 kg of body weight were 3.25, 5.66 and 4.5ng/ml respectively, while those of barrows or gilts were 0.01-0.43ng/ml. 3. The level of androstenone in boars at 110kg of body weight was higher(1.04ng/ml) than that at 70kg of body wight(0.44ng/ml), but there was little difference in the levels of it by body weight or age in barrows and gilts.

These studies were carried out to find the proper conditions for in vitro maturation and fertilization of bovine follicular oocytes and culture methods capable of further developing early embryos. For these objectives, the cleavage rate of oocytes matured and fertilized in vitro was investigated under medium supplemented with hormones and estrous cow serum and season of oocytes collection as well as different cumulus cell stage before insemination. Finally, 2~8 cell embryos were cultured in in vitro and in vitro culture system to investigate developmental capacity into morula. 1. Cleavage rate of oocytes matured in vitro was 27%(20/73) for A(LH＋FSH＋estradil-17$\beta$＋10% FBS), 38%(27/71) for B(LH＋10% ECS) and 27%(15/56) for C(10% ECS), respectively. Supplement B showed more higher rate and 4~8 cell embryos were also obtained much more in this group(67%, 18/27). In vitro maturation rate of follicular oocytes cultured in TCM 199 supplemented withLH and 10% ECS was 88%(75/85). 2. Cleavage rate(15%, 10/65) of oocytes collected in summer was significantly lower than in fall(47%, 42/89). 3. Cleavage rate(15%, 10/65) of oocytes collected in summer was significantly lower than in fall(47%, 42/89). 3. Cleavage rate(15%, 10/65) of oocytes with partially removed cumulus cell before insemination was more higher than that(44%, 27/62) of oocytes with intact cumulus cell. 4. The frequency of development from early cleaved embryos into morula was 6%(4/65), 12%(4/33) for co-culture of cumulus cell monolayer and bovine oviduct epithelial cell monolayer, respectively and 25%(6/25) in ligated rabbit oviduct.

본 실험은 돼지난포란의 체외성숙과 체외수정 효과를 높일 수 있는 방법을 찾기 위하여 시도되었으며 직경 1~2mm와 3~7mm 난포로부터 채란된 난자를 mKRB(-BSA)에 돼지발정혈청(ESS), FCS 또는 투석돼지난포액(DFF)을 첨가한 성숙배양에서 24~48시간, 37$^{\circ}C$에서 배양하였다. 성숙된 난포란은 정소상체 정자와 24시간 배양 후 전핵행성 여부를 조사하였다. 36~48시간 배양에서 50~60%의 난자가 metaphase II에 도달되었고 난포 크기(1~2mm와 3~7mm)간에 체외성숙율의 차이는 없었으나 3~7mm 난포란에서 성숙분열이 다소 빨랐다. 체외성숙배양액에 5% ESS, 15% FCS 및 DFF 첨가시 대조구보다 다소 성숙율이 높았다. 체외수정율(전핵형성)은 5% ESS와 15% FCS 첨가 성숙시킨 난포란과 체내 수정능획득 정자와의 수정에서 각각 높은 경향이 있었다. 따라서 돼지난포란의 체외성숙과 수정에 ESS, FCS 및 투석난포액이 유효한 요인이 됨을 알 수 있다.