• Clinical and Experimental Reproductive Medicine
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• v.18 no.1
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• pp.41-48
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• 1991

The present investigation has been undertaken to elucidate the functional role of ovarian steroids on the mechanism of oviduct differentiation during early embryonic development in rat. The activity of alkaline phosphatase (ALPase) was measured in the oviduct tissue under different steroids treatment regime on day 9 pregnancy. The ALPase activity of the oviduct of pseudopregnant rat was compared with that of normal pregnant rat. The results of day 9 pregnancy rat oviduct clearly demonstrated that $17{\beta}-estradiol$ and progesterone were effective in pseudopregnant rat oviduct. In the ovary intact group the ALPase activity was similar in both of normal and pseudopregnant oviduct, but in the $17{\beta}-estradiol$ treated group the ALPase activity in normal pregnancy was significantly higher than that in pseudopregnancy. The effect of estradiol on the normal pregnant rat oviduct was apparently found on day 3 and day 9 pregnancy. This study, therefore, clearly demonstrates that $17{\beta}-estradiol$ is much potent in oviduct tissue differentiation. It is suggested that absence of $17{\beta}-estradiol$ effect on pseudopregnant rat oviduct is due to there is no embryo passing througth the oviduct.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.2
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• pp.155-161
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• 1995

The present investigation has been undertaken to elucidate the differentiation mechanism the uterus which is the environment of the embryo development, by demonstrating the role of ovarian steroids hormone in the decidualization of the pseudopregnant rat uterus. To determine the effect of ovarine steroids and artificial stimulation (trauma) on the differenciation of the uterine endometrium and decidualization for implantation, attempt was made to measure concentrations of serum estradiol($E_2$), progesterone($P_4$) and nuclear $P_4$ receptor in the traumatized and non-traumatized uterine tissue of the pseudopregnant rat. The results obtained are as followings : The concentration of serum $E_2$ on day 9(implantation stage) was similar in both of intact pseudopregnant rat(47.63pg/ml) and normal pregnant rat(40.71pg/ml). And among the treated groups, $E_2$ concentration was highest in the $E_2$ treated group in comparision with intact control group(relative value; 73.27%). The concentration of serum $P_4$ was also highest in the $P_4$ treated group(23.12pg/ml). Relative value of $P_4$ treated group in comparision with intact group(24.88pg/ml) was 92.93%. The nuclear $P_4$ receptor levels in the artificial traumatized groups were higher compared with the non-traumatized control groups. This study, therefore, clearly demonstrates that the methods for inducing pseudopregnant (vagina tapping;120/min) and inducing decidualization(oil injection; 0.1ml/uterine horn) appear to be effective, $P_4$ appears to be effective in the differenciation of the uterine endometrial tissue for the implantation process. Concentration of serum $P_4$ seems to be well correlated with the level of the nuclear $P_4$ receptor during the early embryo development. These results seem to be well correlated with ALPase activities in the normal and pseudopregnant rat uterus shown in the previous study.

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.139-143
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• 2009

Most captive canids and felids at Zoos in advanced countries have been examined enough to apply artificial reproductive techniques to them. We investigated reproductive hormones and vaginal epithelial cells of a 6-year-old, female coyote, hoping these data could eventually be extended to artificial insemination with frozen-thawed conspecific semen at Seoul Zoo. As a relative of pet dogs, coyote exhibited a similar appearance with only minor differences. In vaginal smear, an increase in the number of superficial cells suggests that the bitch has reached a state close to estrus. A sudden decrease of estradiol and increase of progesterone is considered as a preovulatory event. Vaginal epithelial cells and hormones might be useful for determining the optimal time of artificial insemination in coyotes' breeding.

• Clinical and Experimental Reproductive Medicine
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• v.14 no.2
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• pp.149-158
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• 1987

The present investigation has been undertaken to understand the mechanism of implantation process, by demonstrating the role of ovarian steroids in the differentiation of uterine endometrium for implantation. In particular, an attempt was made to examine the activity of alkaline phosphatase (ALP) in the either luminal, stroma or endometrium tissue sites under the pseudopregnant state induced by ovarian steroid hormones. Attempt was also made to demonstrate the correlate function of ovarian steroids with the cAMP concentration and prolactin level. The higher activity of ALP in the uterine endometrium was observed on day 3. However, the higher activity of ALP in the stroma and epithelium was observed on Day 6. This study, therefore, clearly demonstrates that progesterone is consecutive effect in stroma differ entiation. The cAMP concentrations on Day 3 treated with E or P was lower than those of control. On the other hand concentration on Day 6 treated with hormones was increased than those of control. It is, therefore, concluded that the concentration of cAMP in the uterine tissue undergoing differentiation is decreased. The prolactin level of the treated groups was the lower levels than those of the control groups. It is indicated that there is no effect of ovarian steroid hormone on the prolactin synthesis in this pseudopregnant state.

• Korean Journal of Animal Reproduction
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• v.10 no.2
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• pp.175-181
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• 1986

These experiments were carried out to clarify the effects various kinds of cryoprotectants which were frequently used in freezing embryos of domestic animals on the survival of frozen-thawed mouse embryos. As cryoprotectant, glycerol, DMSO and methanol were used and the procedures of adding them in medium were practiced by one-step or six-step adding method. Morphologically normal mouse embryos developed to blastocyst by in vitro culture after freezing and thawing were transferred to pseudopregnant recipients by surgical procedures. The results obtained in these experiments were summarized as follows: 1. The survival rates of the frozen-thawed 8-cell embryos, morulas and blastocysts following one-step addition of glycerol were 83.6, 80.3 adn 70.3%, respectively, while following six-step addition of glycerol, 69.2, 56.3 and 66.7% respectively. 2. When glycerol, DMSO and methanol were used as cryoprotectant under the same condition of freezing and thawing, the survival rates of frozen-thawed embryos were 74.0, 76.1 and 37.6%, respectively. 3. The implantation rate of embryos transferred to pseudopregnant recipients after freezing and thawing was 49.2%.

• Korean Journal of Animal Reproduction
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• v.8 no.1
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• pp.16-21
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• 1984

This experiment was carried out to compare with the nonsurgical and surgical recovery of fertilized eggs in super-ovulated rabbits. Sixty-four eggs recovered were transferred to twelve synchronized, pseudopregnant rabbits to test the viability of the eggs by surgical transfer. Each group(I, II, III) received a single subcutaneous injection of 5mg PGF2${\alpha}$/kg B.W. at 24(Group I), 48(Group II) and 72 hours (Group III) after mating, respectivity. After the administration of PGF2${\alpha}$, vaginal washings were conducted at 3, 6, 9, 12 and 24 hrs, and frequency of vaginal washing was 5 times for the each group (I, II, III). In Group (IV, V, Ⅵ), the rabbits were killed to recover the fertilized eggs from the genital tract at 24(Group Ⅵ), 48(Group V) and 72 hours (Group Ⅵ) after mating, respectively. The results obtained were as follows: 1. Of the total eggs, 69.3%, 73.4% and 66.9% were recovered for Group I, II and III, respectively from the vagina within 6 hrs after PGF2${\alpha}$ injection and particularly for Group III. 2. The rates of egg recovery versus the number of corpora lutea were 55 (51.6-60%), 35.8 (24-52.6%), 33.4 (25-47%) and 72 (70.7-73.0)%, 60.3 (50-71.4)%, 449(44.4-45.5)% in Group I, II, III and Group IV, V, Ⅵ, respectively. 3. Most of eggs recovered were one-cell stage in Group Iand Group IV. More than one half of the eggs recovered in Group II and V were over eight-cell stage, and most of the eggs were so in Group III and Ⅵ. 4. When sixty-four eggs recovered between 24 to 72 hours after mating were transferred to pseudopregnant rabbits. Three recipients were pregnant, and the rate of pregnancy was 25%.

• Journal of Embryo Transfer
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• v.7 no.2
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• pp.81-88
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• 1992

Cryopreservation of mouse embryos biopsied at 4-cell stage was investigated by ultrarapid freezing. Four-cell embryos were obtained from ICR mice on 55h after hCG injection. Zona pellucida of the embryos were partially dissected with a cutting pipet, and then single blastomeres were biopsied from the embryos followed by incubation in $Ca^2$+ and $Mg^2$+-free M16 medium for 30min. Biopsied embryos cultured for lh or 15h were frozen by ultrarapid freezing method using 3M DMSO or 5M glycerol as a cryoprotectant, respectively. The developmental rate of biopsied embryos after ultrarapid freezing and thawing to blastocysts was 81 % in the group of biopsied embryos cultured for lb and 98% in the group of biopsied embryos cultured for 15h, respectively. When biopsied embryos after ultrarapid freezing and thawing were transferred to the uteri of pseudopregnant recipients, normal live young were born. These results suggest that this freezing method can efficiently cryopreserve biopsied mouse embryos.

• Korean Journal of Animal Reproduction
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• v.13 no.2
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• pp.63-69
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• 1989

Eight-cell mouse embryos equilibrated with vitrification solution(VS3), consisting of glycerol and polyethlene glycol, were plunged directly into liquid nitrogen. The embryos were cryopreserved by vitrification without intra- and extracellular ice formation. After the vitrified embryos were warmed at 4$^{\circ}C$, sucrose dilution procedures were examined and the survival embryos were transferred to recipients after 48h incubation in vitro. The results were obtained as follows. 1. Mouse embryos equilibrated with VS3 were diluted with 1.5m sucrose-HB 1 solution, 0.5M sucrose-HB1 solution for 5min at room temperature, respectively. The proportion of vitrified-warmed embryos developed to blastocyst(85.7%) was as high as that of the embryos diluted with 1.04M sucrose-HB1 solution at 4$^{\circ}C$(85.5%). 2. Normal live youngs were obtained in 53.9%(55/102) of the vitrified-warmed embryos after tranfer to pseudopregnant recipients.

• Korean Journal of Animal Reproduction
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• v.17 no.3
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• pp.201-207
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• 1993

We determined whether the ultrarapid freezing method is applicable to micromanipulated mouse embryos. One-cell mouse embryos were microinjected with MThGH gene. Nuclei from one-cell embryos of F1(C57BL$\times$CBA) mice were transplanted into enucleated one-cell embryos of ICR mice. The injected and nucleated embryos that developed to 2-cell stage were cryopreserved by ultrarapidfreezing. The embryos equilibrated in freezing medium(3 M DMSO＋0.25 M sucrose＋2% FBS in PBS) were directly immersed into liquid nitrogen and then thawed in 37$^{\circ}C$ water. Development rates of the microinjected and nuclear-transplanted embryos to blastocyst stage after ultrarapidly freezing and thawing were 31% and 55%, respectively. The frozen-thawed embryos were transferred to pseudopregnant recipient, which then gave birth to 17 offsprings. Twelve(14% of the transferred embryos) and five(20%) offsprings were derived from microinjected and nuclear-transplanted embryos, respectively. The results indicate that the DNA injected and nuclear-transplanted mouse embryos are cryopreservable at 2-cell stage by ultrarapid freezing method.

• Journal of Embryo Transfer
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• v.6 no.2
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• pp.47-51
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• 1991

This study investigated full-term development potential of ultrarap idly frozen and thawed mouse 2-cell embryos. Mouse 2-cell embryos, dehydrated by exposure to freezing medium, were directly immersed into liquid nitrogen and thawed in 37$^{\circ}C$ water. The embryos that were frozen and thawed were cultured in uitro and transferred to foster mothers to examine there developmental potential. As a result, the frozen-thawed 2-cell embryos developed to blastocysts in vitro as a similar rate as control 2-cell embryos did(in vitro 2-cell, 86.4%; in vivo 2-cell, 90.9%; solution control, 89.9%; control, 89.7%). Normal live young were obtained from transfer of frozen-thawed embryos to the oviduct and uterus of pseudopregnant recipients (3l.4~56.7%).