• Journal of Embryo Transfer
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• v.23 no.4
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• pp.257-261
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• 2008

The objective of present study was to investigate the effect of seasons on reproductive performance of Hanwoo and Holstein heifers. Heat stress in summer or cold stress in winter stress to Hanwoo and Holstein heifers may bring reproduction failure, which would pose an important economic loss, even around Daegwallyeong region located in high mountainous area. Seasonal differences in the serum levels of LH, FSH and progesterone ($P_4$) in response to environmental factors (hot and cold) out of 20 pubertal Hanwoo heifers in Daegwallyeong, Gangwon Province and 20 non-lactating Holstein heifers in Chonan city of Republic of Korea at 2-3 years of age were compared. Blood samples for hormonal analysis were from jugular vein after detection of estrus repeatedly over four seasons within four-week intervals (Spring: May to June, Summer: July to August, Autumn: October to November and Winter: January to February). In Hanwoo heifer population, averages of LH and FSH concentration in spring and in summer were greater compared to those in winter (p<0.05). LH or FSH levels tended to be greater (p=0.06) in spring and less (p=0.09) in winter compared to the levels in autumn. Only in summer, cattle seemed to show lower LH or FSH secretion (p<0.05). Similar to the results in Hanwoo heifers, the serum concentrations of LH and FSH in Holstein heifers decreased further by heat stress in summer when P 4 levels were high during luteal phase. The results demonstrate significant effect of summer heat on reproduction of Hanwoo or Holstein heifers. Although parameters indicating the extent of heat stress were not measured in this study, we suggest that serum hormone levels could be considered as successful indicators of summer heat stress condition for Hanwoo and Holstein heifers even under rather cool summer climate.

• Korean Journal of Animal Reproduction
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• v.8 no.2
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• pp.100-109
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• 1984

This study was conducted to find out the changes of progesterone and estradiol-17$\beta$ levels in the serum of female Korean native goats during the reproductive stages such as the estrous cycle, pregnancy and periparturient period. Nine heads of female Korean native goats of 3 year old in average and weighing 35.7$\pm$1.4 kg were offered for the experiment. Blood samples were taken at 0, 1, 2, 5, 7, 10, 13, 15, 18 and 19 days after onset of estrus, and 1, 30, 60, 90, 120 and 149 days of pregnancy, and -5, -2, -1, 0, +1, +2 and +5 days of periparturient period where minus figures denote the days before paturition. The progesterone, estradiol-17$\beta$ in the serum samples were assayed by radioimmunoassay methods. The results of this study are summarized as follow: 1. The progesterone levels during the estrous cycles reached a peak level of 0.98$\pm$0.60ng/ml at 13 days after onset of estrus and decreased thereafter and were lower than 0.09$\pm$0.02mg/ml on the first day of estrus. 2. The estradioe17$\beta$ levels during the estrous cycles showed a peak level of 15.97$\pm$1.72pg/ml at onest of estrus, and decreased (5.41$\pm$0.51pg/ml-9.09$\pm$1.82pg/ml) during luteal phase. 3. The progesterone levels during the gestation period increased from day 1 and peaked at 90 days after mating and then decreased until 149 days. The peak level was 6.27$\pm$0.23ng/ml at 90 days. 4. The estradiol-17$\beta$ levels during the gestation period showed gradual increase, which were 9.03$\pm$0.88, 32.96$\pm$2.85, 46.03$\pm$2.42, and 54.06$\pm$1.64pg/ml on 30, 60, 90 and 120 dyas after mating respectively. 5. The progesterone levels measured from 5 days before the parturition to 5 days after showed the highest level at the shart of measurement (4.46$\pm$0.31ng/ml) and decreased gradually and bottomed out at one day post-partum and thereafter (0.24$\pm$0.02-0.45$\pm$0.06ng/ml). 6. The estradiol-17$\beta$ levels measured during the same periparturient period as progesterone showed increase to reach the peak level at 1 day before parturition and decreased rapidly thereafter (-5 dyas 69.46$\pm$3.62, -2 days 107.07$\pm$1.91, -1 days 137.83$\pm$7.54, 0 days 50.06$\pm$6.71 and +1 to +5 days 3.21-4.72 pg/ml).

• Clinical and Experimental Reproductive Medicine
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• v.41 no.4
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• pp.158-164
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• 2014

Objective: To assess whether an early GnRH antagonist start leads to better follicular synchronization and an improved clinical pregnancy rate (CPR). Methods: A retrospective cohort study. A total of 218 infertile women who underwent IVF between January 2011 and February 2013. The initial cohort (Cohort I) that underwent IVF between January 2011 and March 2012 included a total of 68 attempted IVF cycles. Thirty-four cycles were treated with the conventional GnRH antagonist protocol, and 34 cycles with an early GnRH antagonist start protocol. The second cohort (Cohort II) that underwent IVF between June 2012 and February 2013 included a total of 150 embryo-transfer (ET) cycles. Forty-three cycles were treated with the conventional GnRH antagonist protocol, 34 cycles with the modified early GnRH antagonist start protocol using highly purified human menopause gonadotropin and an addition of GnRH agonist to the luteal phase support, and 73 cycles with the GnRH agonist long protocol. Results: The analysis of Cohort I showed that the number of mature oocytes retrieved was significantly higher in the early GnRH antagonist start cycles than in the conventional antagonist cycles (11.9 vs. 8.2, p=0.04). The analysis of Cohort II revealed higher but non-significant CPR/ET in the modified early GnRH antagonist start cycles (41.2%) than in the conventional antagonist cycles (30.2%), which was comparable to that of the GnRH agonist long protocol cycles (39.7%). Conclusion: The modified early antagonist start protocol may improve the mature oocyte yield, possibly via enhanced follicular synchronization, while resulting in superior CPR as compared to the conventional antagonist protocol, which needs to be studied further in prospective randomized controlled trials.

• The Korean Journal of Pharmacology
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• v.23 no.2
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• pp.57-75
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• 1987

Two modalities of gonadotropin secretion, pulsatile gonadotropin and preovulatory gonadotropin surge, have been identified in the mammals. Pulsatile gonadotropin secretion is modulated by the pulsatile pattern of GnRH release and complex ovarian steroid feedback actions. The neural mechansim that regulates the pulsatile release of GnRH in the hypothalamus is called "GnRH pulse generator". Ovarian steroids, estradiol and progesterone, appear to exert thier feedback effects both directly on the pituitary to modulate gonadotropin release and on a hypothalamic site to modulate GnRH release; estradiol primarily affects the amplitude while progesterone decreases the frequency of the pulsatile GnRH. Steroid hormones are known to affect catecholamine transmission in brain. MBH-POA is richly innervated by NE systems and close apposition of NE terminals and GnRH cell bodies occurs in the MBH as well as in the POA. NE normally facilitates pulsatile LH release by acting through ${\alpha}-receptor$ mechanism. However, precise nature of facilitative role of NE transmission in maintaining pulsatile LH has not been clearly understood. Close apposition of DA and GnRH terminals in ME might permit DA to influence GnRH release. Action of DA transmission probably is mediated by axo-axonic contacts between GnRH and DA fibers in the ME. Dopamine transmission does not normally regulate pulsatile LH release, but under certain conditions, increased DA transmission inhibit LH pulse. Endogenous opioid acts to suppress the secretion of GnRH into hypophysial portal circulation, thereby inhibiting gonadotropin secretion. However, an interaction between endogenenous opioid peptides and gonadotropin release is a complex one which involves ovarian hormones as well. LH secretion appears to be most suppressed by endogenenous opioids during the luteal phase, at a time of elevated progesterone secretion. The arcuate nucleus contains not only cell bodies for GnRH and ${\beta}-endorphin$ but also a dense aborization of fibers suggesting that GnRH release is changed by the interactions between GnRH and ${\beta}-endorphin$ cell bodies within the arcuate nucleus. The frequency and amplitude of pulsatile LH release seem to be increased during the preovulatory gonadotropin surge. Estradiol exerts positive feedback action on the hypothalamo-pituitary axis to trigger preovulatory LH surge. GnRH is also crucial hormonal stimulus for preovulatory LH surge. It is unlikely, however, that increased secretion of GnRH during the preovulatory gonadotropin surge represents an obligatory neural signal for generation of the LH discharge in primates including human. Modulation of preovulatory LH surge by catecholamines has been studied almost exclusively in rats. NE and E may be involved in distinct way to accumulate GnRH in the MBH and its release into the hypophysial portal system during the critical period for LH surge on proestrus in rats. However, the mechanisms whereby augmented adrenergic transmission may facilitate the formation and accumulation of GnRH in the ME-ARC nerve terminals before the LH surge have not been clearly understood.

• Development and Reproduction
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• v.3 no.1
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• pp.29-38
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• 1999

The pathogenesis of endometriosis is unknown, but retrograde menstruation is widely accepted as an etiology. Refluxed endometrium from endometriosis patients is more prone to implant and invade peritoneum possibly through the action of extracellular proteolysis. This proteolytic action may involve plasminogen activators and the collagenase system. Plasminogen activators (PAs) and matrix metalloproteinases (MMPs) play a critical role in the breakdown of extracellular matrix components and basement membrane in the processes of implantation and tumor invasion. PAs are inhibited by plasminogen activator inhibitor (PAI) and MMPs activity is inhibited by tissue inhibitor of metalloproteinase (TIMP). To test the hypothesis that lower expression of PAI-1 and TIMP-3 in endometrium from women with endometriosis, we investigated their PAI-1 and TIMP-3 expression by quantitative competitive RT PCR in endometrium from women with and without endometriosis. Endometrial tissues were obtained from 14 patients with severe endometriosis and 14 patients without endometriosis. Total RNA was extracted and reverse transcribed into cDNA, and quantitative competitive PCR (QC PCR) was performed to evaluate PAI-1 and TIMP-3 mRNA expression. Endometrium from patients with endometriosis showed decreased expression of PAI-1 and TIMP-3 mRNA compared to endometrium from control in luteal phase (p<0.05). Our results suggest that endometrium from women with endometriosis expresses lower levels of PAI-1 and TIMP-3 than endometrium from normal women. Endometrium from endometriosis patients may be more invasive and prone to peritoneal implantation than control because of higher PA and MMP enzymatic activity. Thus, increased proteolytic activity may be one of the reasons for the invasive properties of the endometrium resulting in the development of endometriosis.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.3
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• pp.355-362
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• 1999

Objective: This study was performed to compare the clinical response to controlled ovarian hyperstimulation (COH) of in vitro fertilization and embryo transfer (IVF-ET) according to the size of baseline ovarian cyst. Method: From February 1992 to March 1999, a retrospective analysis was done of 272 cases who underwent COH using mid-luteal phase long protocol of gonadotropin-releasing hormone agonist (GnRH-a) for IVF-ET. These cases were divided into four group; group 1 (n=63) had cysts with mean diameters between 20.0 and 29.0 mm on their baseline ultrasound on cycle day 3, group 2 (n=57, $30.0{\sim}49.0mm$), group 3 (n=68, >50.0 mm) and control group (n=84). Cases were excluded according to the following criteria; pure male factor infertility, the presence of only one ovary, high CA-125 level and previous endometriosis. Results: There were no statistically significant differences between cases with baseline ovarian cyst <50.0 mm in diameter and control group in any of the parameters. However, cases with baseline ovarian cyst>50.0 mm in mean diameter needed more amount of human menopausal gonadotropin (hMG), showed significantly lower estradiol ($E_2$) level, the number of follicle >15.0 mm on the day of human chorionic gonadotropin (hCG) administration, the number of oocytes retrieved, the number of mature oocytes, and pregnancy rate compared with control group. Conclusion: This study suggests that cases with baseline ovarian cyst <50.0 mm in diameter do not adversely impact on IVF-ET outcome. However, cases with baseline ovarian cyst >50.0 mm in diameter had adverse effects on various parameters. Therefore, to improve the outcome of IVF-ET in these cases, ovarian cyst aspiration prior to initiating COH may be required.

• Journal of Embryo Transfer
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• v.24 no.4
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• pp.289-292
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• 2009

Mongolia has 80% livestock of total agriculture industry, 170,000 farms are engaged, 2,500,000 of cows that were beef and dairy cows are raised. Despite of Mongolian has great application with milk, there are not clear differences between cow and dairy cattle, and the production of milk is also low. But the milk suppliers are varied (horse, sheep, goat, etc), so that the total milk production is 500 thousand ton per year. It's really considerable to improve the breed of owing to many problems with big differences among milk qualities. For carrying out for first year project, artificial insemination project was operated with 3rd grade Holstein semen that were imported from S. Korea, and initiation and field training were also carried out through appropriate AI technique we developed for Mongolia environment. Local information research and MOU conclusion were done with professor D. Altangerel in May $10^{th}{\sim}13^{th}$, 2009, and development for AI technique and AI equipments were supplied for Mongolia breeding and natural environment in July $10^{th}{\sim}17^{th}$ in 2009. All cows were treated by synchronization for AI. To do this, $PGF_{2\alpha}$ injection were treated for luteal phase cow, if it wouldn't work, try again after 11 days. After confirmation of estrus, AI and AI training were carried out with sperm injection in the uterus or cervix by rectum-vagina method which is common worldwide, the most effective artificial insemination technique. If cows were return to next estrus cycle, second AI was carried out about approximately 21 days after artificial insemination. After 2 months, all cows not showing return estrus should be taken pregnancy test. Every pregnant cow will be cared thoroughly. Total 48 cows administrated by $PGF_{2\alpha}$ for synchronization and after 48 hours 45 cows (93.8%) showing estrus were detected and then artificial inseminate them within who 8 cows (27.8%) showed return estrus. Therefore, Using $PGF_2{\alpha}$ for synchronization is effective to use for Mongolia breeding conditions. There are possibility of base for food production after all, including increase of livestock production in Mongolia by improvement of breeding cow with AI and embryo transfer project.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.175-180
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• 1999

Blood chemical values and sex steroid hormone concentration of repeat breeder and reproductive disorder in Hanwoo, which were bred in Chunchon areas, were examine to establish the basic physiological maker. The concentrations of albumin, blood urea nitrogen(BUN), calcium(Ca), cholesterol, creatinine, glucose, phosphorous, total protein and triglycerides in repeat breeder and reproductive disorder were 3.28$\pm$0.05 and 3.27$\pm$0.04 g/㎗, 11.07$\pm$0.61 and 12.69$\pm$0.88 mg/㎗, 9.98$\pm$0.10 and 9.56$\pm$0.11mg/㎗, 105.75$\pm$3.57 and 126.78$\pm$5.66mg/㎗, 1.62$\pm$0.05 and 1.65$\pm$0.09 mg/㎗, 67.46$\pm$9.07 and 76.97$\pm$3.76mg/㎗, 6.13$\pm$0.36 and 6.11$\pm$0.26mg/㎗, 5.82$\pm$0.08 and 6.18$\pm$0.08 g/㎗ , 12.82$\pm$1.46 and 15.19$\pm$1.61mg/㎗, respectively. Among the blood chemical values, Ca, cholesterol and inorganic phosphorous levels in repeat breeder and reproductive disorder were slightly higher than those in normal cows. The progesterone levels of pregnancy(0.18~6.56 ng/$m\ell$) and non-pregnancy(0.15~5.46ng/$m\ell$) cows at estrus cycle were showed similar trends from 0 day to 18 days. Those of pregnancy cows were increased gradually from 18 days to 180 days(5.90~7.51 ng/$m\ell$), while those of non-pregnancy cows were dramatically drop at 21 days (0.18$\pm$0.03mg/㎗). The concentrations of estrogen and progesterone in repeat breeder and reproductive disorder were 57.42$\pm$5.03, 56.76$\pm$8.73 pg/$m\ell$ and 6.26$\pm$0.83, 9.41$\pm$1.85 ng/$m\ell$ . respectively. These results indicate that blood chemical values in repeat breeder and reproductive disorder were not greatly difference in normal cows except for Ca, cholesterol, BUN and inorganic phosphorous. Since the progesterone levels in repeat breeder and reproductive disorder was maintained to the luteal phase levels of normal cows, it may cause of failing of conception and next estrus cycle.

• Proceedings of the KSAR Conference
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• 2000.10a
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• pp.10-12
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• 2000

Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$-subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$ -subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was. efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to consist of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t63I or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632-653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agonist-occupied receptors ~2- and ~17-fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.357-364
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• 2000

Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$ -subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$-subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t631 or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632~653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agoinst-occupied receptors ~2- and ~17- fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.