• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.774-780
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• 2009

The objectives of this study were to test the efficacy of induction of estrus and determine the timing of ovulation in relation to preovulatory LH and estrogen surges in cycling Murrah buffaloes subjected to Heatsynch protocol (GnRH-$PGF_2{\alpha}$-Estradiol benzoate). In experiment 1, the buffaloes (n = 10) were treated with Heatsynch protocol and observed for estrus and ovulation. In experiment 2 and 3, 30 cycling Murrah buffaloes were used to investigate the efficacy of Heatsynch protocol in terms of conception rates in summer (experiment 2) and winter (experiment 3) seasons. Fixed time A.I. was performed in all the buffaloes at 48 and 60 h post-estradiol benzoate (EB) injection. All buffaloes responded to the Heatsynch protocol with expression of estrus for which ovulations were induced in 8 buffaloes (80%). Mean time interval from the EB injection to ovulation was 50.0${\pm}$2.0 h (range 44.0 to 60.0 h). The interval from the end of LH surge to ovulation was 18.5${\pm}$2.47 h (range 8 to 26 h). The interval from end of estrogen surge to ovulation was 26.75 ${\pm}$2.07 h (range 22 to 36 h). Mean LH peak after EB injection occurred at 20.81${\pm}$1.61 h (range 14 to 28 h) and mean estrogen peak after EB injection occurred at 9.62${\pm}$1.03 h (range 7 to 16 h). Hence, the mean estrogen peak preceded the mean LH peak by 11 h. It was observed that the percentage of conceptions to total number of estruses for control buffaloes was 18 and 30 in summer and winter, respectively, whereas it increased to 26 and 40 in Heatsynch treated buffaloes in respective seasons. The results suggest the possibility of using Heatsynch treatment followed by fixed time A.I. in buffaloes for fertility improvement, especially since the incidence of silent heat in buffaloes is very high.

• Clinical and Experimental Reproductive Medicine
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• v.20 no.2
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• pp.131-135
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• 1993

The ultrasonographic examination with vaginal probe(5MHz) was undertaken in 101 patients at infertility clinic of Eul-Ji General Hospital. This study was performed to evaluate the number of mature follicles per menstrual cycle, the relationship of both ovaries for consecutive ovulatory cycle and the responsiveness of follicular growth followed by administration of ovulation inductant. The results were as follows; 1. The ovulation induction group with clomiphene citrate showed more follicles than natural menstrual cycle group. 2. Each means of numbers of follicles between ovaries showed no difference between natural and ovulatory induction groups. 3. The rate of follicular growth per one menstrual cycle showed higher in the clomiphene citrate induced cycle group. 4. Clomiphene citrate induced group tends to be easier for multiple follicular growth but had no significant difference in statistics. 5. The ipsilateral Vs. contralateral follicular growth rate for consecutive menstrual cycles in both ovaries showed no significant difference between two groups.

• Reproductive and Developmental Biology
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• v.35 no.4
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• pp.519-525
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• 2011

Growth hormone (GH) is obligatory for growth and development. But, there is controversy on the GH effect about reproductive processes of sexual differentiation, pubertal maturation, gonadal steroidogenesis, gametogenesis and ovulation. This study was conducted to investigate the effect of GH on estrus, ovulation and embryo implantation. The results obtained were as follows. GH stimulated to increase estrus rate (p<0.05), pregnancy rate (p<0.05), and total fetus number in mice treated for superovulation. Also, the correlation between GH and steroids, E2 and P4, at peri-estrus stage/ peri-ovulation stage/ peri-implantation stage of the superovulation-induced mice was examined. Consequently, GH co-injected with PMSG especially increased P4 level (p<0.05) at peri-estrus stage of superovulationinduced mice. In conclusion, GH co-treatment in superovulation system boosted the rate of estrus, pregnancy and total fetus by increasing progesterone level at peri-estrus stage of superovulation-induced mice.

• Journal of Aquaculture
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• v.13 no.1
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• pp.47-53
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• 2000

Hormone induction in maturation and ovulation was carried out with spotted halibut (Verasper variegatus) which normally does not spawn spontaneously in captivity. Prior to spawning females were treated with human chorionic gonadotropin(HCG 265-678 IU/kg BM) 17 ${\alpha}$-hydroxy 20-${\beta}$-dihydroprogesterone (17 ${\alpha}$ 20${\beta}$ OHP 0.5-1.0${\mu}$g/kg BW) and luteinizing hormone-releasing hormone analogue pellet (LHRHa pellet 63-81 ${\mu}$g/kg BW) In all the trials HCG injection succeeded in inducing ovulation at 265-300 IU/kg BW. HCG at 620 or 678 IU/kg BW was ineffective in inducing a good rate of ovulation. Final maturation and ovulation were not stimulated by treatment of 17 ${\alpha}$ 20${\beta}$OHP and LHRHa pellet. These results suggest that HCG injection (around 300 IU/kg BW) is more effective compared with LHRHa pellet implantation.

• Journal of Aquaculture
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• v.11 no.2
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• pp.151-158
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• 1998

Effects of intraperitoneal administration of LHRH-a (luteinizing hormone releasing hormone analogue), pimozide and HCG (human chorionic gonadortropin) were studied on ovulation in the bullhead, Pseudobagrus. fulvidraco. Ovulatin was induced in 71.4, 80 and 100% by injection of HCG 5,000, 10,000 and 20,000 IU/kg of body weight, respectively. Also, the majority of fish injected with LHRH-a in the presence or absence of pimozide were ovulated. The ovulating rates in fish injected with LHRH-a alone showed 50, 75 and 100% at a dose 200, 300 and $400^{\mu}$g/kg, respectively. Pimozide enhanced the activity of LHRH-a at $300^{\mu}$g/kg plus pimozide at 1 mg/kg. Pimozide alone was ineffective in inducing ovulation of P. fulvidraco. There were no significant differences in gonadosomatic index (GSI) and pseudo-GSI values among the groups treated with HCG, LHRH-a and LHRH-a plus pimozide (P>0.05). The latency time groups treated with HCG was 17~22 hours, and the group injected with LHRH-a alone and/or in combination with pimozide was ovulated within 23~29 hours.

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.187-193
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• 2003

Recently a protocol was developed that precisely synchronizes the time of ovulation in Hanwoo. Cows were treated with GnRH on Day 0, PGF$_2$$\alpha$ 7 d later, GnRH 2 d later, and then time-inseminated approximately 24 h after this second treatment with GnRH. Ovarian morphology was monitored cows by trans-rectal ultrasonography 6.5MHz linear transrectal probe(Sonovet - 600., Medison co. Korea) from 24 hr to 31 hrs after second GnRH injection. The result obtained summarized as follows - 1. Induced ovulation were 24 to 31hr after the second GnRH injection, but high induced ovulation was 28hr. 2. Conception rate with HML(High meat lin) and HIL(High milk lin) treatment were 48.1％(38/79) and 43.9％(40/91), respectively. 3. Conception rate of 1∼2 parity and 3∼4 parity was 44.3％ and 55％, respectively. 4. Conception rate of spring, autumn was more increased, 47.3％ than summer.

• Development and Reproduction
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• v.1 no.1
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• pp.67-77
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• 1997

Mammalian ovary consists of various growing stages of follicles. Ovarian follicular growth and differentiation, however, can be distinguished into recruitment, growth, selectiona nd ovulation. while only minute of the selected follicles ovulate their oocytes, all the rest follicles disappear by atresia. this atresia is an important event of which physiological mechanism must be resolved. The present study was carried out to investigate the effects of various doses of pregnant mare's serum gonadotropin (PMSG) on the oocyte quality, ovulation rate, and the early embryonic development in immature mice. Immature mice were administrated with 5, 20, or 40 IU PMSG. At every 12 hour up to 72 hour after treatment, body and ovary weights were measured. Oocytes were flushed from the oviducts under the dissecting microscope and observed under the inverted microscope. Late 2-cell embryos were collected from the mice which were superovulated by the same dosage of PMSG followed by 5 IU hCG 47 hours after PMSG-treatment. The percentage of abnormal oocytes was higher in 20 or 40 IU PMSG-treated animals than 5 IU PMSG-treated ones. Ovulation occured at 12 hours afger PMSG injection in all experimental groups. The percentage of retrieved abnormal oocytes increased in the 20 or 40 IU PMSG-treated goups but not in 5 IU PMSG-treated group. There was no significant difference in the mating rate among the groups [52.6% (10/19), 66.7% (10/15), 44.0% (11/25) : 5, 20, 40 IU group respectively] ; however, ther was a significant (p<0.01) increase of embryo retrieval rates in 5 and 20 IU-treated groups compared with that in 40 IU-treated group [89.2% (239-268), 85.5% (224/262), 40.0% (18/45)]. There was significant (p<0.01) increase of embryo development rates in 5 IU-treated group compared with that in 20 and 40 IU-treated group [231/239(96.7), 179/224(79.9), 77.8(14/18)]. In conclusion, higher doses of PMSG injection increased the occurrence of abnormal oocytes ovulation in immature mice. The most of oocytes collected from 5 or 20 IU-PMSG-treated group has fertilizabioity. But in mice injected iwth higher doses of PMSG, their oocytes exhibit less fertilizability and, even fertilized, all oocytes are not fully capable of development.

• Journal of Life Science
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• v.8 no.5
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• pp.576-581
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• 1998

The present study was carried out to investigate the effect of gonadotropin administration on the timing of ovula-tion, fertlizable life of eggs and cleavage of embryos in rabbit. Mature angora rabbits were primed for superovulation with PMSG 100IU. Eighty hours later, the rabbit were induced to ovulate with HCG 100IU. Ovulation had started at 10hours after HCG injection and finished at about 16hours. Fertilizable life of eggs were lasted for 8hours after ovulation. The most frequent developmental stage observed from the embryos recovered at 24, 48, 72, 96, and 120 hours after HCG injection was 2-ceIL, 16-cell, morula, blastocyst and blastocyst, respectively.

• 대한생식의학회:학술대회논문집
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• 2006.06a
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• pp.6-11
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• 2006

Our previous study demonstrates a rapid activation of atypical PKC${\zeta}$ by the ovulatory dose of LH/hCG. The present study was therefore designed to identify PKC${\zeta}$ regulated-genes in rat ovarian preovulatory granulosa cells. Preovulatory granulosa cells cultured in the presence of myristoylated PKC${\zeta}$ pseudosubstrate peptide were subjected to identify differentially expressed genes by using anneling control primer RT-PCR. As a result, among sixteen genes identified, six genes (testin, glypican-4, retrovirus SC1, connective growth factor, aminolevulinic acid synthase1 and serum- inducible kinase) were rapidly stimulated by hCG. Northern blot analysis demonstrated that all these genes were rapidly stimulated by hCG and declined thereafter. In situ hybridization analysis revealed the expression of these genes in granulosa cells of preovulatory follicles. The present study demonstrates time- and cell-specific expression of PKC${\zeta}$-regulated genes, and may imply that these genes play a specific role(s) during LH-induced ovulation.

• Journal of Embryo Transfer
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• v.12 no.1
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• pp.117-122
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• 1997

The objective of this study was to enhance the pregnancy rate of repeat-breeder Hanwoo with gonadotropin-releasing hormone(Gn-RH) at the time, dose and site of administration.The results obtained were summaried as fallows:1.Ovulation time and pregnancy rate following GnRH administration time was 46.0, 27.4, 42.0 and 43.2hr and 33.3, 57.1, 37.5 and 40.0% at non-treatment, estus, 1st A' and 2nd Al treatment, respectively.2. Ovulation in repeat-breeder was induced 100% within 24hr with GnRH administration at the time of estrus.3. Ovulation time and pregnancy rate following GnRH adminstration dose and site was 25.2, 32.6, 17.6 and 27.6hr, and 28.6, 42.9, 75.0 and 66.7% at 50$\mu$g+IU, 50$\mu$g+IM, 100$\mu$g+IU and 100$\mu$g+IM treatments, respectively. It is concluded that GnRH administration for repeat-breeder was enhanced the pregnancy rate when treated with 100$\mu$g intrauterine at the time of estrus.