• Clinical and Experimental Reproductive Medicine
• /
• v.35 no.2
• /
• pp.111-118
• /
• 2008

Objective: The purpose of the present study was to examine the hormonal regulation of RGS-2 in the rat ovary. Methods: Immature rats were injected with 10 IU of PMSG to induce multiple growth of preovulatory follicles and 10 IU of hCG to induce ovulation. Northern blot analysis performed for gene expression and in situ hybridization performed for mRNA localization. Results: Northern blot analysis revealed that pregnant mare's serum gonadotropin (PMSG) treatment did not affect RGS-2 mRNA levels. In contrast, human chorionic gonadotropin (hCG) treatment of PMSG-primed rats resulted in an increase in RGS-2 expression within $1{\sim}3\;h$. The major cell-types expressing RGS-2 mRNA were oocytes regardless of follicle size. Interestingly, hCG treatment caused the stimulation of RGS-2 gene expression in granulosa cells of preovulatory and growing follicles. In contrast, cell types expressing RGS-2 protein were theca cells regardless of hCG treatment. Like in vivo, treatment of preovulatory granulosa cells with LH in vitro stimulated RGS-2 levels within 1 h. Interestingly, GnRH antagonist II enhanced the stimulatory action of LH. Conclusion: The present study demonstrates the LH/hCG induction of RGS-2 in preovulatory granulosa cells and suggests a role of RGS-2 in Gq protein signaling pathway during ovulation.

• Journal of Veterinary Clinics
• /
• v.19 no.4
• /
• pp.418-425
• /
• 2002

Estrus was induced in 13 anestrus Korea Jin-do bitches by intramuscular injection of pregnant mare serum gonadotropin (PMSG) in a dose of 500 lU once daily for ten consecutive days, followed by an additional single intraveneous injection of 1,000 lU of human chorionic gonadotropin (hCG) on the tenth day. Day-changes of vaginal epithelial cells during the hormone treatment were investigated in each experimental bitches and compared with the those of spontaneous estrus bitches. The first days of vulval bleeding and male acceptance after PMSG treatment were on Day 6.0$\pm$ 1.5 (mean$\pm$ SD) and Day 9.0$\pm$ 1.9, respectively. And in all of 13 bitches, vulval swelling and perineal reflex were shown. The mean durations of proestrus and estrus were 2.9$\pm$ 1.4 (mean$\pm$ SD, range ; 1-6) and 11.5: 1.7 (range ; 8-14) days, respectively, that is, duration of proestrus was significantly shorter than that of the spontneous estrous bitches but duration of estrus was longer than that of the spontaneous estrous bitches. Characteristic features of vaginal cytology during the estrous cycle were the high proportions of large intermediate cell, superficial cell, anuclear cell and erythrocyte in proestrus, superficial cell and anuclear cell in estrus and parabasal cell, small intermediate, large intermediate cell, and leukocyte in diestrus, respectively. The comification index (Cl) was significantly high proportion in proestrus and estrus, when Day 0 was timed from the first day of male acceptance, the Cl was first increased above 80% on Day 0 and maintained above 80% until Day 0 to Day 5 during 6 days and showed a peak on Day 2. Also it was maintained above 90% until Day 2 to Day 3 during 2 days. These results indicated that all 13 ekperimental bitches showed positive estrus detection by the estrus behavior and vaginal smear test after treated with PMSG and hCC. It suggested that vaginal cytology was used to estimate the optimal mating and ovulation time, in consideration of the day when the Cl was maintained above 80% in estrus-induced Korea Jin-do bitches.

• Korean Journal of Veterinary Research
• /
• v.49 no.4
• /
• pp.285-290
• /
• 2009

This study was performed to investigate the possibility of superfecundation by surgical intrauterine artificial insemination in dogs of confirmed genetic pedigree. Artificial insemination was performed on 3 days after ovulation with $1.3{\times}$ $10^8$ spermatozoa. Five puppies were delivered on 60 days after insemination. The ratio of the number of newborns to the number of corpora lutea was 83.3% (5/6). Parentage analysis with 10 canine-specific microstatellite markers demonstrated that one puppy was genetically relative to the sire-A family and four puppies were genetically relative to the sire-B. The present study demonstrated that two kinds of puppies with different genetic pedigree can be produced by surgical uterine insemination of semen of individual dog into each uterine horn of a bitch.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.18 no.1
• /
• pp.192-206
• /
• 2005

Objective : To know about ovarian hyperstimulation syndrome pathophysiology, risk factors and clinical features and to research the trend of the study related to OHSS. Methods : We referred a PubMed site by using searching word of "ovarian hyperstimulation syndrome"(Limits: 1 Year, only items with abstracts, Human). Results : 28 journals with 49 papers were searched. Conclusion 1. The study of OHSS subjects on pathophysiology, prevention and medical treatment. 2. As OHSS is an exaggerated response to ovulation induction therapy, it's emphasized that aspect of prevention OHSS. 3. Preventing OHSS are the following. The first is to give a GnRH agonist or antagonist in substitute for hCG. The second is to screen out prevalence of thrombophilia. The third is to monitor $E_2$ levels. The forth is to aspirate of Mediculous follicle. The fifth is cryopreservation of all embryos. The sixth is that administration of albumin for treatment of OHSS. But, it's not useful to administration of albumin for prevention of OHSS. 4. There's no therapy of OHSS. But, there's only symptomatic treatment of OHSS.

• Journal of Veterinary Clinics
• /
• v.15 no.1
• /
• pp.94-99
• /
• 1998

This study was carried out to determine the effects of uterus shortening on the duration required for estrus, the number of ovulation and the level of serum progesterone and prostaglandin $F_{2}{\alpha} (PGF_{2}{\alpha} $). The duration required for estrus after the surgical shortening of uterine horns and the interval between the following estrus was not affected by the surgical treatment but affected by luteal and follicular phase. The number of ovulations were increased by induction of superovulation to gilts with shortened uterine horns compared to the control. Serum progesterone concentration during the luteal phase was higher than that during the follicular phase with no difference between the control and me horns than that of the control. Findings of this study indicate that luteal formation and regressions and estrus cycle were normal when the unconnected parts of uterine horns were left in abdominal cavity. Therefore surgical shortening of uterine horns of sows helps embryo collections by non-surgical methods.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.1
• /
• pp.173-181
• /
• 1992

Duck is an important domestic animal, especially in Asia. Eighty five percent of ducks in the world are kept in Asia, especially in the East and South Asia regions. The ancestor of domesticated ducks was mallard (Anas platylhynchos), which are still migrating between north and southern parts in Eurasia. Ducks have been domesticated in China for at least 3000 years ago. Phylogenetic studies on ducks, employing electrophoresis of blood proteins, indicate a marked difference of genetic constitution between duck breeds in southeast Asia and those in northeast Asia. Duck embryonic ovary is much more active in secretion of sex steroid hormones especially estradiol than the embryonic testes. Estradiol secreted by the embryonic left ovary has an important role in female sexual differentiation in ducks. In the female ducks, plasma LH, estradiol and testosterone levels increase and reach peaks shortly before the first egg, while progesterone level reach a peak shortly after the first egg. In laying ducks oviposition mostly occurs in the last 3 hr of darkness and first hr of light ranging 02:00-06:00 under 14 hr light (05:00-19:00) and 10 hr darkness photoperiodic condition. Measurements of plasma hormone levels reveal that onset of darkness is a major signal for LH release from the pituitary and the subsequent release of progesterone from ovary, and for induction of ovulation in the female duck.

• Clinical and Experimental Reproductive Medicine
• /
• v.28 no.1
• /
• pp.47-53
• /
• 2001

Objective: This study is to investigate the clinical efficacy of low-dose FSH regimen, comparing with clomiphene citrate and human menopausal gonadotropin (CC/hMG) regimen. Methods: Retrospective study of the ovulatory factor infertility 39 patients who had been treated by intrauterine insemination (IUI). The 31 cycles of 21 patients were stimulated by CC/hMG regimen, the 22 cycles of 18 patients were stimulated by low-dose FSH regimen. We compared the rate of clinical pregnancy, multiple pregnancy and ovarian hyperstimulation syndrome (OHSS) of both group. Results: The rate of clinical pregnancy of the CC/hMG group was 25.7% per cycle, and that of the low-dose FSH group was 54.5% per cycle. The low-dose FSH group showed a higher rate of clinical pregnancy per cycle than CC/hMG group (p=0.028). However, no differences was found statistically in the rate of multiple pregnancy and OHSS between CC/hMG group (22.2%, 5.7%) and low-dose FSH group (33.3%, 13.6%). Conclusion: This study showed that the low-dose FSH regimen is superior to CC/hMG regimen in getting clinical pregnancy, but dose not reduce the ovulation induction complications.

• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.11
• /
• pp.1673-1685
• /
• 2019

Objective: To evaluate the efficacy of treatments based on gonadotrophin-releasing hormone (GnRH), GnRH-prostaglandin $F2{\alpha}$ ($PGF2{\alpha}$), and/or intense exposure to novel rams to induce fertile estrus without the use of steroid hormones in seasonally anestrous Suffolk ewes. Methods: In the first experiment, ewes were treated with one injection of GnRH, two injections of GnRH administered 7 days apart, or a sequence of GnRH-$PGF2{\alpha}$-GnRH (GPG). In the second experiment anestrous ewes were exposed, for 36 days starting on the day of weaning, to groups of four rams of three different breeds that were alternated every day. Besides exposure to the male effect (ME), the ewes were injected with saline solution (ME group, n = 20), with GnRH (ME-GnRH group, n = 20) or with a sequence of GnRH-$PGF2{\alpha}$-GnRH (ME-GPG group, n = 20). The rams used for male-effect were fitted with aprons to prevent mating, and ewes detected in estrus were bred to selected fertile rams. Ovarian activity was monitored by progesterone determinations in both experiments. Results: In the first experiment sustained induction of ovarian activity was not achieved and no ewe was detected in estrus. In the second experiment induction of sustained ovarian activity was achieved in all groups. Most of the ewes were detected in estrus, 76.7% of the ewes were mated during a 36-d breeding period and 71.7% of all the ewes became pregnant during that period. No significant differences between groups were found for any of these variables. However, estrus detection efficiency was higher in the ME-GnRH group than in the ME group (p<0.05). Conclusion: An intense male-effect, that included the continuous presence and frequent alternation of several rams of different breeds, was sufficient to induce ovarian activity and fertile estrus in Suffolk ewes during the period of deep anestrus without the use of hormones, although addition of GnRH improved the efficiency of estrus detection.

• Development and Reproduction
• /
• v.4 no.2
• /
• pp.187-193
• /
• 2000

Gonad and blood samples were taken from the cultured female Korean sea bass, Lateolabrax japonicus from October to February between 1997 and 1999. Gonadosomatic index began to increase in November and reached the highest value in December (12.8$\pm$1.5) and January (14.8$\pm$3.5), and then decreased sharply in February (2.6$\pm$1.5, p<0.05). The ovarian oocytes developed to tertiary yolk stage and reached fully-Brown stage in December and January, and then underwent atresia without maturation and ovulation in February. The plasma estradio3-17 $\beta$ level increased from November, and reached the highest value in December (1,152.3$\pm$107.2 pg/ml) and January (1,315.4$\pm$99.5 pg/ml), after then decreased in February (P<0.05). The concentration of plasma 17 $\alpha$ ,20 $\beta$-dihydroxy-4-pregnen-3-one was not significantly changed at low levels (86.6$\pm$6.5∼93.8$\pm$2.8 pg/ml) during the experimental period (P<0.05). All the fish with fully-grown oocytes in the ovary were matured and ovulated by HCG injection. The number of floating eggs were 325,000$\pm$26,000 at HCG 1,000 luhg and 195,000$\pm$35,000 at 2,000 lUikg. There was no difference in fertilization rate and hatching rate of the eggs (P<0.05). Considering these results, we could infer that the ovarian oocyte of the cultured Korean sea bass were not matured and ovulated because of the lack of gonadotropin surge. Moreover, HCG injection could induce oocyte maturation and ovulation in the cultured fish, and the effective dose was 1,000 IU/kg.

• Clinical and Experimental Reproductive Medicine
• /
• v.36 no.2
• /
• pp.111-119
• /
• 2009

Objective: The aim of this study was to compare the clinical efficacy of clomiphene citrate (CC) and letrozole combined with gonadotropins for controlled ovarian stimulation (COS) in patients with CC-induced thin endometrium Methods: Fifty-one intrauterine insemination cycles performed in patients who previously had a thin endometrium (<8 mm) to ovulation induction using CC were included in this study. A CC 100 mg/day (CC+gonadotropin group, n=26) or letrozole 2.5 or 5 mg/day (letrozole+gonadotropin group, n=25) was administered on day 3~7 of the menstrual cycle, combined with gonadotropins at dose 75~150 IU every other day starting on day 5~7. We compared total dose of gonadotropin used, endometrial thickness, endometrial pattern, number of follicles ${\geq}14\;mm$ on hCG day, pregnancy rate and multiple pregnancy rate between the two groups, which were statistically analyzed using Mann-Whitney U test or Fisher's exact test, where appropriate. Results: There were no significant differences in clinical characteristics such as age, duration of infertility, number of previous IUI cycles, basal serum hormone levels and cause of infertility between the two groups. In both groups, the endometrium was significantly thicker than that of previous ovulation induction cycles using CC. No significant differences were found in the total dose of gonadotropin used, day of hCG administration, the rate of triple endometrium and pregnancy rate. The number of follicles ${\geq}14\;mm$ was significantly lower ($3.7{\pm}1.7$ vs. $2.8{\pm}1.7$, p=0.03) and the endometrium on hCG day was significantly thicker ($7.7{\pm}1.5$ vs. $9.1{\pm}1.7$, p=0.001) in letrozole+gonadotropin group compared to CC+gonadotropin group. Conclusion: The clomiphene citrate and letrozole combined with gonadotropins appear to avoid the undesirable effects on the endometrium frequently seen with CC for ovulation induction. However, in terms of adequate endometrial development or optimal follicular growth, letrozole may be more beneficial than CC for gonadotropin-combined COS in patients with CC-induced thin endometrium. Further prospective randomized controlled studies in a larger scale will be necessary to confirm our findings.