• Clinical and Experimental Pediatrics
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• 제55권9호
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• pp.337-343
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• 2012

Purpose: Leptin has been considered a link between metabolic state and reproductive activity. Defective reproductive function can occur in leptin-deficient and leptin-excessive conditions. The aim of this study was to examine the effects of centrally injected leptin on the hypothalamic KiSS-1 system in relation to gonadotropin-releasing hormone (GnRH) action in the initial stage of puberty. Methods: Leptin (1 ${\mu}g$) was injected directly into the ventricle of pubertal female mice. The resultant gene expressions of hypothalamic GnRH and KiSS-1 and pituitary LH, 2 and 4 hours after injection, were compared with those of saline-injected control mice. The changes in the gene expressions after blocking the GnRH action were also analyzed. Results: The basal expression levels of KiSS-1, GnRH, and LH were significantly higher in the pubertal mice than in the prepubertal mice. The 1-${\mu}g$ leptin dose significantly decreased the mRNA expression levels of KiSS-1, GnRH, and LH in the pubertal mice. A GnRH antagonist significantly increased the KiSS-1 and GnRH mRNA expression levels, and the additional leptin injection decreased the gene expression levels compared with those in the control group. Conclusion: The excess leptin might have suppressed the central reproductive axis in the pubertal mice by inhibiting the KiSS-1 expression, and this mechanism is independent of the GnRH-LH-estradiol feedback loop.

• 한국발생생물학회지:발생과생식
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• 제1권2호
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• pp.189-202
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• 1997

The hypothalamic peptide GnRH plays a central role in the regulation of the mammalian reproductive axis. Recent studies suggested that GnRH stimulates or inhibits the ovarian steroidogenesis and gametogenesis directly. Our previous report indicated that GnRH gene is expressed in adult rat ovary as well as in hypothalamus and that the expressed GnRH may induce the follicular atresia and apoptosis of ovarian granulosa cells in rat. Therfore, we studied whether GnRH gene is expressed in the mouse fetal ovary, when the germ cells are degenerating by apoptosis during gonad diffeerentiation. Mouse fetal gonads were obtained on the 12, 15,18 and 20th day of gestation from the mother mice superovulated (10 IU PMSG and 10 IU hCG) and mated. The morphological changes of fetal ovaries were examined histochemically by hematoxylin-eosin staining. The fetal sex was confirmed by PCR methods for sexing. RT-PCR methods were used to examine the expression of GnRH gene and the sex steroid hormones were determined by conventional radioimmunoassays. The levels of estradiol (E) and progesterone (P) were increaseduntil 18th day of gestation and then E was decreased just before parturition. The morphological changes of fetal gonadal tissue sections showed the ovarian development and coincided with the result of PCR analysis for sexing using ovary- or testis- specific oligonucleotide primers. Immunoreactive GnRH in placenta was decreased gradually until the end of gestation but fetal brain and ovarian GnRH were increased. The level of GnRH gene expression was increased during fetal ovarian development from 12 till 18th day and decreased suddenly on 20th day just before birth. From these results, it is suggested that ovarian GnRh may play a regulatory role on the germ cell differentiation of fetal ovary.

• 한국발생생물학회지:발생과생식
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• 제7권1호
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• pp.35-40
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• 2003

성선자극호르몬 분비호르몬은 시상하부에서 분비되며, 포유동물의 생식에 중추적인 역할을 담당한다. 골든 햄스터는 계절적으로 번식하는 포유동물이며, 생식 활동은 광주기(하루 중 낮의 길이)에 의해 결정된다. 장주기(12.5 시간 이상의 빛)는 생식 능력을 유지시키지만, 단주기(12시간 이하의 빛)는 생식 기능을 억제한다. 성선자극호르몬 분비호르몬과 광주기의 상호 관계를 자세히 조사하기 위하여 랫트 성선자극호르몬 분비호르몬 cDNA를 포함하는 벡터를 여러 농도로 골든 햄스터의 수컷에 주입하고 단주기에 유지하여 생식 활동을 개별적으로 조사하였다. 벡터를 고농도로 처리한 그룹의 골든 햄스터는 기타 실험 그룹에 비해 정소 퇴화가 의미있게(P<0.05) 가속되었다. GnRH의 맥동적 분비가 생식 능력을 유지하는 관점에서 보면, GnRH-cDNA를 포함하는 벡터는 GnRH를 일정하게 고농도로 분비했다고 사료된다. 이 결과는 GnRH를 포함하는 벡터가 뇌하수체 전엽을 desensitization시켜 정소 퇴화를 가속시켰음을 암시한다.

• Journal of Yeungnam Medical Science
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• 제30권2호
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• pp.90-94
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• 2013

Background: This study was conducted to examine if basal luteinizing hormone (LH) levels could be useful for screening central precocious puberty (CPP) in girls. Methods: A total of 90 girls under the age of 8 years were included in this study. They underwent the gonadotropin-releasing hormone (GnRH) stimulation test at Good Gang-An Hospital from March 2008 to December 2012 for evaluation of premature sexual development. Patients were classified into two groups: the pubertal response group of patients who had 5 IU/L peak LH levels in the GnRH stimulation test, and the prepubertal response group of patients who had LH levels <5 IU/L. Chronological and bone ages, height, weight, body mass index, gonadotropin response to GnRH stimulation, and basal levels of LH, follicle-stimulating hormone, and estradiol were studied in both groups. The relationship between basal LH and peak-stimulated LH was evaluated using Spearman's correlation. To determine the optimal cut-off values of basal LH levels for differentiating between two groups, the receiver operating characteristic (ROC) curves were analyzed. Results: When the correlation between basal LH levels and peak LH after GnRH stimulation was analyzed in all subjects (N=90), basal LH levels had a statistically significant positive correlation with peak stimulated LH levels (rs=0.493, p<0.001). The cut-off level of optimal basal LH was 0.1 IU/L, according to the ROC curves. Its sensitivity was 73.3%, and its specificity was 77.8%. Conclusion: The study results showed that serum basal LH levels are useful for screening CPP in girls.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
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• pp.249.2-249
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• 1998

No Abstract, See Full Text

• 한국동물학회지
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• 제33권4호
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• pp.435-445
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• 1990

시상하부에서 합성, 분비되는 gonadotropin releasing horrnone (GnRH)의 면역반응성이 생식소를 비롯한 여러 부위에서도 검출됨이 알려졌으나, 이 펩타이트가 과연 생식소에서 국부적으로 합성되는 지에 관해서는 아직 밝혀지지 않았다. 본 연구에서는 흰쥐 생식소에서 GnRH유전자발현을 연구하기 위하여 GnRH-like mRNA와 GnRH펩타이트의 발현과 세포내 분포 양상을 조사하였다. GnRH 방사면역측정법과 GnRH를 크로마토그라피 방법으로 분리한 결과,시상하부에서 합성되는 GnRH와 유사한 GnRH 면역반은이 흰쥐 생식소 추출물에서 상당량 검출되었다. GnRH-면역반응이 흰쥐 난소의 다양한 세포군에서 나타냄에 반하여, GnRH-like mRNA는 granulsa,theca 그리고 luteal 세포에서만 주로 발현되었다. 또한 흰쥐 정소에서 GnRH면역반응성은 원시정세포, Sertoli,Leydig 세포에서만 검출된 반면에, GnRH-like mRNA는 정세관내의 Seertoli세포에서만 발현되었다. 따라서 이 연구는 생식소에 존재하는 GnRH는 생식소 내에서 국부적으로 합성, 발현되는 결과라고 사료되며, 생식소 내에서 생성된 GnRH는 생식소내 세포군간의 정보교환의 매개자로서 역활을 수행하고 있다고 추정된다.

• 한국수정란이식학회지
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• 제23권2호
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• pp.109-114
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• 2008

This study examined pregnancy and fetal loss rates according to different estrus synchronization protocols and injection of gonadotropin releasing hormone (GnRH) after transfer of Korean Native Cattle embryos to Holstein recipients. In Experiment 1, recipients received no treatment (Control, n = 119); two injections of prostaglandin$F_{2{\alpha}}$ ($PGF_{2{\alpha}}$ ) 11 days apart (PGF group, n = 120); GnRH (day 0)-$PGF_{2{\alpha}}$ (day 7)-GnRH (day 9) (Ovsynch group, n = 120); and CIDR (day 0)-$PGF_{2{\alpha}}$ and CIDR removal (day 7)-GnRH (day 9) (CIDR group, n = 110). In Experiment 2, the control group was received no treatment of GnRH. The treatment groups were received GnRH at embryo transfer (ET) (day 0), 7 days later, 14 days later, ET and 7 days later, 7 and 14 days later, or ET, 7 and 14 days later. Recipients were assigned to treatment randomly and received two in vitro produced blastocysts. Pregnancy was diagnosed at day 60 by palpation per rectum. Fetal loss to term was determined by palpation every 90 days thereafter. In Experiment 1, the pregnancy rate in the CIDR group (59.1%) were higher than in the Control group (42.0%) (p<0.01); fetal loss rates were similar for all groups (12.0 to 18.5%). In Experiment 2, the pregnancy rate in Day 0+7+14 group was higher (60.2%) than the control (40.2%) (p<0.01) and resulted in a lower fetal loss (p<0.05) than the control (4.6 vs. 11.4%). There were no significant difference between other treatment and the control (p>0.05). These results show that pregnancy rates of bovine embryos can be enhanced by CIDR insertion or GnRH $3{\times}$ treatment. Additionally, fetal loss may be reduced with GnRH treatment after ET.

• 한국수산과학회지
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• 제56권3호
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• pp.309-314
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• 2023

Shark populations are constantly decreasing owing to environmental destruction and overfishing; thus, sharks are now at risk of extinction, with 30.5% of species classified as endangered on the International Union for Conservation of Nature's Red List. Sharks are apex predators and keystone species in balancing the marine food chain; their extinction would create an imbalance in the entire marine ecosystem. Assisted reproductive technology is a last resort for protecting animals facing extinction. Here, as a proactive effort toward building a hormone-induced artificial insemination protocol for endangered wild sharks, we identified the possibility of germ cell maturation by administration of GnRH, a commercially produced synthetic salmon gonadotropin-releasing hormone, and calculated its optimum dosage and injection timing. The experiment was conducted on one shark species, Chiloscyllium plagiosum. Injections were administered in 24 h intervals to C. plagiosum females, and 0.2 mL/kg+0.2 mL/kg were the optimal doses. These doses effectively induced maturation and, and ovulation, and oocyte release. Our results confirm that GnRH is a suitable tool for shark hormone-induced artificial insemination and indicate that this method may facilitate the conservation of endangered shark species.

• 한국발생생물학회지:발생과생식
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• 제4권2호
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• pp.231-236
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• 2000

Gonadotropin-releasing hormone (GnRH)과 그 수용체가 흰쥐의 난소, 정소, 자궁, 태 반 그리고 유선 등의 생식기관에서 발현됨이 알려져 있다. 더욱이, 뇌하수체 전엽에 작용하는 GnRH의 표적 산물로 알려진 luteinizing hormone (LH)이 흰쥐 생식소에서도 발현됨이 알려졌는데, 이는 생식소 내에 GnRH-LH로 이루어진 국부 회로 (local circuit)가 존재함을 시사하는 것이다 본 연구는 LH와 그 수용체 유전자가 흰쥐 유선에서도 발현되는가를 규명한 것이다. 이를 위해 reverse transcription-polymerase chain reaction (RT-PCR)과 LH 방사면역측정법 (radioimmunoassay, RIA)을 사용하였다. RT-PCR을 시행한 결과 생식 주기중인 임신하지 않은 흰쥐 유선에서 뇌하수체 유형의 LH${\beta}$ 전사체 (exon 1-3)가 증폭되었으나 정소특이적 LH${\beta}$ exon 부분은 검출되지 않았다. 뇌하수체 glycoprotein hormone에서 공통적으로 존재하는 ${\alpha}$-subunit과 LH 수용체에 대한 전사체 역시 흰쥐 유선에 존재함이 확인되었다. 또한 기존의 보고에서 수유중인 흰쥐 유선에서만 발현된다고 알려진 GnRH가 임신하지 않은 흰쥐 유선에서도 발현됨을 확인하였다. LH 방사면역측정법을 시행한 결과 흰쥐 유선조직 추출물에서 immunoreactive LH분자들이 검출되었으며, LH standard curve와 parallelism을 보이므로 흰쥐 유선의 LH가 뇌하수체 형과 동일할 가능성을 확인하였다. 본 연구는 흰쥐 유선에서 LH subunit들과 수용체 유전자가 발현됨을 최초로 보고한 것으로서, 흰쥐 유선이 LH의 생성처이면서 동시에 작용처이며 유선에서 합성된 GnRH의 조절하에 국부적인 인자로 작용할 가능성을 시사한다.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 공동 춘계학술대회
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• pp.70.2-70
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• 1999

No Abstract, See Full Text