• Fisheries and Aquatic Sciences
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• 제14권4호
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• pp.379-388
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• 2011

The mechanism by which gonadotropin-releasing hormone (GnRH) and dopamine (DA) control gonadotropin (GTH) release was studied in male and female rainbow trout using cultured pituitary cells obtained at different reproductive stages. The mechanisms of follicle-stimulating hormone (FSH) release by GnRH and DA could not be determined yet. However, basal and salmon-type GnRH (sGnRH)- or chicken-II-type GnRH (cGnRH-II)- induced luteinizing hormone (LH) release increased with gonadal maturation in both sexes. LH release activity was higher after sGnRH stimulation than cGnRH-II stimulation at maturing stages in both sexes. The GnRH antagonist ([Ac-3, 4-dehydro-$Pro^1$, D-p-F-$Phe^2$, D-$Trp^{3,6}$] GnRH) suppressed LH release by sGnRH stimulation in a dose-dependent manner, although the effect was weak in maturing fish. The role of DA as a GTH-release inhibitory factor differs during the reproductive cycle: the inhibition of sGnRH-stimulated LH release by DA was stronger in immature fish than in maturing, ovulating, or spermiated fish. DA did not completely inhibit sGnRH-stimulated LH release, and DA alone did not alter basal LH release. Relatively high doses ($10^{-6}$ or $10^{-5}M$) of domperidone (DOM, a DA D2 antagonist) increased LH release, which did not change with reproductive stage in either sex. The potency of DOM to enhance sGnRH-stimulated LH release was higher in maturing and ovulated fish than in immature fish. These data suggest that LH release from the pituitary gland is controlled by dual neuroendocrine mechanisms by GnRH and DA in rainbow trout, as has been reported in other teleosts. The mechanism of control of FSH release, however, remains unknown.

• Animal cells and systems
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• 제5권3호
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• pp.217-224
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• 2001

The present study examines the expression and regulation of gonadotropin-releasing hormone (GnRH) and its receptor (GnRH-R) mRNA levels during mouse ovarian development. A fully processed, mature GnRH mRNA together with intron-containing primary transcripts was expressed in the immature mouse ovary as determined by Northern blot analysis and reverse transcription-polymerase chain reaction (RT-PCR). The size of ovarian GnRH mRNA was similar to that of hypothalamus, but its amount was much lower than that in the hypothalamus. Quantitative RT-PCR procedure also revealed the expression of GnRH-R mRNA in the ovary, but the estimated amount was a thousand-fold lower than that in the pituitary gland. We also examined the regulation of ovarian GnRH and GnRH-R mRNA levels during the follicular development induced by pregnant mare's serum gonadotropin (PMSG) and/or human chorionic gonadotropin (hCG). Ovarian luteinizing hormone receptor (LH-R) mRNA was abruptly increased st 48 h after the PMSG administration and rapidly decreased to the basal level thereafter. Ovarian GnRH mRNA level was slightly decreased at 48 h after the PMSG administration, and then returned to the basal value. GnRH-R mRNA level began to increase at 24 h after the PMSG treatment, decreased below the uninduced basal level at 48 h, and gradually increased thereafter. HCG administration did not alter ovarian GnRH mRNA level, while it blocked the PMSG-induced increase in GnRH mRNA level. Taken together, the present study demonstrates that the expression of GnRH and GnRH-R mRNA are regulated by gonadotropin during follicular development, suggesting possible intragonadal paracrine roles of GnRH and GnRH-R in the mouse ovarian development.

• Clinical and Experimental Reproductive Medicine
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• 제21권3호
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• pp.241-245
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• 1994

Despite increasing success rate of IVF, poor response to ovarian stimulation remains a problem. So, attempts to improve ovarian responses, for example, by using combined gonadotropin-releasing hormone analogue(GnRH-a) and human menopausal gonadotropin(hMG) have shown limited success. It is reported that response of granulosa cells in vitro to FSH is stimulated by co-incubation with IGF-l, and IGF-l production can be increased by growth hormone. This suggest that combination regimen of G.H. and hMG may augment follicle recruitment. In fifteen patients who had previous history of poor ovarian response to gonadotropin stimulation after pituitary suppression with mid -luteal GnRH-a, the effectiveness of cotreatment with G.H. in IVF program was evaluated using a combination regimen of G.R. and hMG at Korea University Hospital IVF Clinic. Ovarian responses to gonadotropin stimulation in control and GH-treated cycles assessed by total dose and duration of hMG treatment, follicular development and peak $E_2$ level, number of eggs retrieved, and fertilization rates were also assessed. In each group, serum and follicular fluid IGF-1 concentrations on day of egg collection were measured by RIA after acidification and extraction by reveresed phase chromatography. Patients receiving G.H. required fewer days and ampules of gonadotropins, developed more oocytes, and more embryos transferred. But, the differences were not statistically significant, except the duration of hMG treatment. Our data showed a significantly higher concentration of IGF-l in the serum, not in the follicular fluid, of patients treated with G.H. compared with control group. These data suggest that growth hormone treatment does not improve the ovarian response in women with limited ovarian reserve to gonadotropin stimulation for IVF.

• 한국수정란이식학회지
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• 제33권4호
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• pp.297-304
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• 2018

The purpose of the present study was to determine the elaborate characteristics of ovarian changes including follicles and corpus luteum, and hormonal patterns of gonadotropin surge mode secretions during the normal consecutive estrous cycle in three dairy cows. Non-lactating and multiparous Holstein cows (n=3) used as experimental animals. The cows were assigned to examine the relationship among ovarian changes (follicle, corpus luteum), ovarian steroids (estradiol, progesterone) and gonadotropin (LH, FSH) surge mode secretion during the successive estrous cycles by rectal palpation, ultrasonography and hormonal assay. The mean length of the estrous cycle for the three cows was $23.1{\pm}1.44days$ (${\pm}SEM$), with a range of 20-28 days. In six estrous cycles, the number of two follicular waves, three follicular waves and four follicular waves was 2, 3 and 1, respectively. The sequential ultrasonographic monitoring showed that the corpus luteum with ${\geq}10mm$ in diameter detected from Day 2 (Day 0 is ovulation) in six estrous cycles of all cows. Preovulatory increases in estradiol concentration reached $10.36{\pm}1.10pg/ml$ on the 2 days before ovulation of the last dominant follicle. All cows exhibited a preovulatory rise in estradiol concentration followed by a typical preovulatory LH and FSH surge. The mean interval from the peak of LH/FSH surge to ovulation of the last dominant follicle was $31.3{\pm}1.76h$ (${\pm}SEM$). In these results, each dairy cow showed that ovarian morphological changes and gonadotropin surge mode secretion will be regulated by various environmental factors including age, breeds, nutrition, breeding conditions, etc.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2004년도 춘계학술발표대회
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• pp.221-221
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• 2004

Equine chorionic gonadotropin (eCG), which consists of highly glycosylated α- and β-subunits, is a unique member of the gonadotropin family because it elicits response characteristics of both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in other species than the horse. To determine whether α and β subunits can be synthesized as a single polypeptide chain (tethered-eCG) and also display biological activity, the tethered-eCG molecule was constructed and transfected into Chinese hamster ovary (CHO-K1) cells. (omitted)

• 한국임상수의학회지
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• 제21권2호
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• pp.109-114
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• 2004

The effect of Human Menopausal Gonadotropin(hMG) on the implantation, pregnancy, and the concentration of plasma progesterone were studied in pregnant rats. HMG 75 or 150 IU were administered once on day 1, 2, 3, 4, 9, 12 or 14 of gestation, respectively. Rats were autopsied on day 7 or 18. A single dose of hMG prevented implantation and terminated pregnancy in all of the rats by injecting on either day 1 or day 2 and this abortifacient action was effective 82-98% of pregnant rats on day 3 or 4 and 14-20% on day 9 or 12. Administration of hMG had no effect on termination of pregnancy on day 14. Plasma progesterone concentration by injecting hMG on day 1, 2, 3 or 4 were very decreased.

• 약학회지
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• 제41권3호
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• pp.365-369
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• 1997

Human chorionic gonadotropin (hCG) is a placental hormone and is involved in maintenance of the corpus luteum during pregnancy. In the present study, effect of hCG on nitiric ox ide (NO) generation from peritoneal macrophage was examined. hCG ahd no effect on NO generation by itself, whereas recombinant interferon- ${\gamma}$ (rIFN-${\gamma}$) alone had modest activity. When hCG was used in combination with rIFN-${\gamma}$, there was a marked cooperative induction of NO generation in a dose-dependent manner. The optimal effect of hCG on NO generation was shown at 6 hr after treatment with rIFN-${\gamma}$. Furthermore, northern blot analysis of showed that hCG increased the expression of inducible NO synthase(iNOS) gene. These results suggest that hCG induces NO generation from macrophages by increasing the expression of iNOS gene.

• Journal of Nutrition and Health
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• 제8권1호
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• pp.65-69
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• 1975

Human chorionic gonadotropin hormone(H.C.G.) is secreted from the villus tissues of the placenta and excreted in lange amount into the urine. Its isolation is chiefly made from the urine of a pregnant woman. Recently, Matsushima attempted isolation of H.C.G. directly from the placenta itself. In order to prepare H.C.G. from human placenta, general method of extractiag and purifying proteins was applied. Its way was as follow: Crude H.C.G. was extracted from placenta with pH 9.0 and pH 5.0 aqua ammonia, and purified with pH 8.0 ammonia and 50% ethanol at pH 4.8. The purified H.C.G. showed two moving bands on the anode by paper electrophoresis. On the other hand, the H.C.G. from pregnancy urine (Standard. Pharm. Co.) showed same two bands but their moving ratio were different. The purified H.C.G. showed gonadotropin effect when it was injected young fomale rats 40r/cc per day for 5 days and weighted the increased ovary weight.

• 한국발생생물학회지:발생과생식
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• 제22권2호
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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.

• Clinical and Experimental Reproductive Medicine
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• 제48권1호
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• pp.11-26
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• 2021

Advances in anticancer treatments have resulted in increasing survival rates among cancer patients. Accordingly, the quality of life after treatment, particularly the preservation of fertility, has gradually emerged as an essential consideration. Cryopreservation of embryos or unfertilized oocytes has been considered as the standard method of fertility preservation among young women facing gonadotoxic chemotherapy. Other methods, including ovarian suppression and ovarian tissue cryopreservation, have been considered experimental. Recent large-scale randomized controlled trials have demonstrated that temporary ovarian suppression using gonadotropin-releasing hormone agonists (GnRHa) during chemotherapy is beneficial for preventing chemotherapy-induced premature ovarian insufficiency in breast cancer patients. It should also be emphasized that GnRHa use during chemotherapy does not replace established fertility preservation methods. All young women facing gonadotoxic chemotherapy should be counseled about and offered various options for fertility preservation, including both GnRHa use and cryopreservation of embryos, oocytes, and/or ovarian tissue.