• 대한생식의학회:학술대회논문집
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• 2002.11a
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• pp.23-30
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• 2002

• Development and Reproduction
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• v.22 no.2
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• pp.119-132
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• 2018

GnRH (gonadotropin-releasing hormone) is a supreme hormone regulating reproductive activity in most animals. The sequences of amino acid and nucleic acid of GnRH reported up to now are examined from the evolutionary framework of Chordata. All identified GnRH are classified into GnRH1, GnRH2, or GnRH3. In all three forms of GnRH both N-terminal and C-terminal are conserved, which allows for effective binding to their receptors. The three amino acids in the middle of GnRH1 sequence have altered diversely from the primitive Chordata, which is indicative of the adaptation process to the ambient environment. GnRH2 and GnRH3 sequences are well conserved. There are more diverse modifications in the nucleic acids than in amino acid sequence of GnRH1. These variations can result from meiosis, mutation, or epigenetics and indicate that GnRH is the product of natural selection.

• The Korean Journal of Zoology
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• v.37 no.2
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• pp.161-173
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• 1994

면역효소법을 이용하여 3종의 한국산 개구리 참개구리(Rono nigromaculuto), 옴개구리(R. rugosa), 북방산개구리(R. 겨대bowskii)의 뇌에서 GnRH 뉴우런의 분포 부위와 GnRH의 종류 등을 연구하였다. 1차 항체로는 anti-rat GnRH, anti-salmon GnRH anti-chicken 11 GnRH 항체를 사용하였다. 3종의 개구리에서 mGnRH cGnRH 11와 sGnRH가 이둔 동정되었으나 3가지 항체에 대한 각 종의 면역 반응성은 종에 따라 달리 나타났다 mGnRH는 옴개구리와 참개구리에서, sGnRH는 북방산개구리에서 강한 면역 반응을 나타냈으며 cGnRH 11는 3종의 개구리에서 중간 정도의 면역 반응을 나타냈다. 각각의 GnRH의 상대적인 양에는 차이가 있으나 일부 경우를 제외하고는 뇌의 동일한 지역에 분포하였다. 참개구리에서는 GnRH가 중격 내측핵(NMS), Broca band 핵(NDB)에 집단으로 분포하였다. 북방산개구리에서는 GnRH가 중격 내측핵, Broca bnad 핵에서 등쪽에서 배쪽으로 길게 선상으로 가장 협소하게 분포하였으며, 번식기와 직전(1월-3월)에만 면역 반응을 나타냈다. 옴개구리의 뇌에서 가장 광범위한 지역, 즉 종뇌의 중격 내측핵, Broca band 핵, 아래 교차 지역(SCA)과 간뇌에 GnRH 신경세포가 분포하였으며. 제3뇌실 맥락얼기에서 mGnRH 신경세포가 처음으로 동정되었다. 3종에서 공통적으로 중격 내측핵과 Broca band 핵에서 유래한 신경섬유는 복측 시상하부를 거쳐 정중융기에 이르렀다. 이러한 결과는 GnRH가 뇌하수체에서 생식소 자극 호르몬의 분비 조절에 밀접한 관계가 있음을 뜻한다.

• Animal cells and systems
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• v.3 no.1
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• pp.1-7
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• 1999

Gonadotropin-releasing hormone (GnRH) was originally isolated as a hypothalamic peptide that regulates reproduction by stimulating the release of gonadotropins. Using comparative animal models has led to the discovery that GnRH has a more ancient evolutionary origin. Durinq evolution GnRH peptide underwent gene duplication and structural changes to give rise to multiple molecular forms of GnRHs. Mammalian GnRH initially considered to be the sole molecular form, is now grouped as a family of peptides along with GnRH variants determined from representatives in all classes of vertebrates. Vertebrate species including primates and humanshave more than one GnRH variant in individual brains; a unique GnRH form in the forebrain and chicken IIGnRH in the midbrain. Furthermore, several species of bony fish have three molecular variants of GnRH: salmon GnRH sea-bream GnRH and chicken II GnRH. Also, it has been shown that in addition to the olfactory placodes and the midbrain, there is a third embryonic source of GnRH neurons from the basal diencephalon in birds and fish, which might be true for other vertebrates. Therefore, comparative animal models like fish with discrete sites of expression of three molecular variants of GnRH in individual brains, could provide insight into novel functions of GnRH variants, conservation of gene regulation, and mechanisms governing reproduction in vertebrates.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.207-213
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• 2003

This objective of this experiment were to evaluate the effect of various estrus synchronization programs on estrus detection rate and pregnancy rate in Hanwoo. After Postpartum 60 Days, a total of 150 cows divided into 2 groups. Cows Group 1 were treated with one luteolytic dosage of PGF$_2$$\alpha$(25 mg, im; lutalyse. USA) on Day 0, and with a second dosage 14 d later; cows in Group 2 were treated with GnRH(l00 $\mu\textrm{g}$, im; Conceral. Korea) on Day 0, PGF$_2$$\alpha$ 7 d later, GnRH 2 d later, and then time-inseminated approximately 16 h after this second treatment with GnRH. Ovarian morphology was monitored cows by trans-rectal ultrasonography from 24 hr to 32 hrs after second GnRH injection. The result obtained summarized as follows: 1. Cows synchronization of estrus with GnRH+PGF$_2$$\alpha$+GnRH(Ov-synch) and PGF$_2$$\alpha$ were 91.3 and 40.0%, respectively. 2. Induced ovulation were 24 to 32hr after the second GnRH injection, but high induced ovulation was 28hr. 3. High conception rate were 24hr insemination after the second GnRH injection. 4. Conception rate with PGF$_2$$\alpha$, CIDR and GnRH treatment were 50.0, 36.0 and 76.9%, respectively.

• Journal of Aquaculture
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• v.11 no.4
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• pp.513-519
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• 1998

Ovulation of maturing femal mandarin fish, Siniperca scherzeri was induced using single injection of human chorionic gonadotropin (HCG) or gonadotropin releasing hormone-analogue (GnRH-a), GnRH-a plus prostaglandin F2 (PG$F_2$) or GnRH-a plus pimozide. The response was evaluated by fertilization, embryo-formation and hatching rate after insemination. Those rates were generally higher in GnRH-a group than in HCG group. The higher hatching rat of above 89% was achived using a dosage of 5,000 IU/kg HCG plus 10 ${\mu}$g/kg GnRH-a, 10${\mu}$g/kg GnRH-a plus 500 ng/kg PGF2, and 10 ug/kg GnRH-a plus 1-5 mg/kg pimozide. Ovulation was induced in all female injected with sex-maturation hormones and stimulator, but blocked in female injected with HCG plus GnRH-a plus dopamine combination, and GnRH-a plus PGF2 plus indometacin combination. These results show that the mandarin fish in spawning period secrete a sex-mutruation assosiated hormones and gonadotropin-releasing -inhibiting factor(GRIF).

• Animal cells and systems
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• v.13 no.4
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• pp.429-437
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• 2009

The control mechanism of gonadotropin-releasing hormone (GnRH) on gonadotropin (GTH) release was studied using cultured pituitary cell or cultured whole pituitary obtained from Testosterone (T) treated and control immature rainbow trout. The release of FSH was not changed by salmon type GnRH (sGnRH), chiken-II type (cGnRH-II), GnRH analogue ([des-$Gly^{10}D-Ala^6$] GnRH ethylamide) and GnRH antagonist ([Ac-3, 4-dehydro-$Pro^1$, D-p-F-$Phe^2$, D-$Trp^{3,6}$] GnRH) in cultured pituitary cells of T-treated and control fish. Indeed, FSH release was not also altered by sGnRH in cultured whole pituitary. All tested drugs had no effect on the release of LH in both culture systems of control fish. The levels of LH, in contrast, such as the pituitary content, basal release and responsiveness to GnRH were increased by T administration in both culture systems. In addition, the release of LH in response to sGnRH or cGnRH-II induced in a dose-dependent manner from cultured pituitary cells of T-treated fish, but which is not significantly different between in both GnRH at the concentration examined. Indeed, LH release was also increased by sGnRH in cultured whole pituitary of T-treated fish. GnRH antagonist suppressed the release of LH by sGnRH ($10^{-8}\;M$) and GnRH analogue ($10^{-8}\;M$) stimulation in a dose-dependent manner from cultured pituitary cells of T-treated fish, and which were totally inhibited by $10^{-7}\;M$ GnRH antagonist. These results indicate that the sensitivity of pituitary cells to GnRH is elevated probably through the T treatment, and that GnRH is involved in the regulation of LH release. GnRH-stimulated LH release is inhibited by GnRH antagonist in a dose-dependent manner. The effects of gonadal steroids on FSH levels are less clear.

• Fisheries and Aquatic Sciences
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• v.3 no.1
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• pp.37-43
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• 2000

We used a mammalian GnRH antagonist, $[Ac-3,4-dehydro-Pro^1,\;D-p-F-Phe^2,\;D-Trp^{3.6}]$-GnRH, to examine the details of the salmon type gonadotropin-releasing hormone (sGnRH) and GnRH agonist analog $(Des-Gly^{10}$[d-Ala^6]-ethylamide GnRH; GnRHa) functions in the control of maturational gonadotropin (GTH II) secretion, in precocious male rainbow trout, in both in vivo and in vitro experiments. In the in vivo study, plasma GTH II levels increased by sGnRH or GnRHa treatment, but the response was more rapid and stronger in the GnRHa treatment group. The increase in GTH II was significantly suppressed by the GnRH antagonist, while the antagonist had no effect on basal GTH II levels in both groups. The GnRH antagonist showed stronger suppression of GTH II levels in the sGnRH treatment fish than in the GnRHa treatment fish. In addition, plasma androgenic steroid hormones (testosterone and 11-ketotestosterone) increased by the sGnRH or GnRHa treatment. The GnRH antagonist significantly inhibited the increases in plasma androgenic steroid hormone levels stimulated by the sGnRH or GnRHa, while the antagonist had no effect on basal androgenic steroid hormone levels in both groups. In the in vitro study, treatment with sGnRH or GnRHa increased GTH II release from the cultured dispersed pituitary cells, but the response was stronger in the GnRHa treatment group. The increase in GTH II release by GnRH was suppressed by adding the GnRH antagonist, dose­dependently. On the other hand, basal release of GTH II did not decrease by the GnRH antagonist treatment in both groups. These results suggest that the GnRH antagonist, $[Ac-3,4-dehydro-Pro^1,\;D-p-F-Phe^2,\;D-Trp^{3.6}]-GnRH$, used in this study is effective in blocking the action of GnRH-induced GTH II release from the pituitary gland both in vivo and in vitro.

• Development and Reproduction
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• v.5 no.1
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• pp.81-88
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• 2001

Gonadotropin-releasing hormone (GnRH) has been known to play a role in the regulation of hCG secretion by human placenta. Recently, a gene encoding the second f개m of GnRH (GnRH-II) was identified in human. Herein, we demonstrate that GnRH-II is expressed in human placenta and assess GnRH-II expression by nested RT-PCR and immunohistochemistry in human placenta during the first trimester. We found that two altematively spliced transcripts of GnW-II mRNA were expressed in human placental tissues of first trimester and the shorter variant had a 21-bp deletion in GnRH-associated peptide (GAP). Immunoreactive GnRH-II was localized in both cytotrophoblastic and syncytiotrophoblastic cytoplasm. The immunostaining intensity was stronger in cytotrophoblast. Villous stromal cells also showed GnRH-II immunoreactiyiry. The results of our study report that the second isoform of GnRH (GnRH-II) is expressed in the first trimester human placenta and we suggest that GnRH-II may also play a regulatory role in maintenance of early pregnancy and hCG secretion in human placenta.

• Journal of Veterinary Clinics
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• v.3 no.1
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• pp.227-233
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• 1986

A total of 600 Holstein cows in Chonnam province was examined to make a diagnosis on the ovarian follicular cyst. By clinical signs and rectal examination, 57 cows were found to have ovarian follicular cyst. Attempts were made to treat the cows which had ovarian follicular cyst with GnRH, HCG respectively. The results obtained were summarized as follows : 1. The rates of estreous induction with GnRH or HCG were 91.4%, 77.2%, respectively. The GnRH treated group was showed significantly higher than HCG treated group. The mean days from the GnRH or HCG treated to estrum were 25.1 and 23.5 days, respectively. 2. The Conception rates with GnRH or HCG treatment were 78.2% and 76.5％, respectively. 3. Services per conception with GnRH or HCG treatment were 1.5 and 2.1 respectively. 4, Days from GnRH or HCG treatment to concept were 38.2 and 45.8 days, respectively. 5. Intramuscular injection with GnRH and intraovarian injection with HCG were revealed the most effective routes in all the other routes.