• Development and Reproduction
• /
• v.6 no.2
• /
• pp.131-139
• /
• 2002

Since GnRH and its receptor genes are expressed in the ovary, it has been suggested that ovarian GnRH might be involved in the regulation of ovarian function and the apoptosis of ovarian cells. However, it was not known well on the expression and function of GnRH and its receptor in the corpus luteum. The present study was undertaken to investigate whether GnRH and its receptor are expressed in luteal cells and GnRH has any effect on the apoptosis of luteal cells. Luteal cells obtained from the pregnant rats were cultured and stained for GnRH and its receptor proteins. Cultured luteal cells showed distinct immunoreactivity against both anti-GnRH and anti-GnRH receptor antibodies. In addition, the presence of GnRH receptor protein in cultured cells was confirmed by Western blot analysis. To investigate the effect of GnRH on the apoptosis of luteal cells, luteal cells were cultured in the presence of 10$^{-6}$ M GnRH-agonist(GnRH-Ag) for 3, 8, and 12h. TUNEL assay showed that the number of cells undergoing apoptosis increased 12h after culture(P<0.05). DNA fragmentation analysis confirmed the results such that the cells treated for 12h showed the greatest increase of fragmentation(p<0.05). Further, Western blot analysis of cytochrome c in the mitochondrial and cytoplasmic fractions of the luteal cells showed that GnRH-Ag treatment increased the content of cytochrome c in cytoplasm. These results demonstrate that the luteal cells express GnRH and its receptor and GnRH-Ag treatment induces apoptosis of the luteal cells via mitochondrial release of cytochrome c. The present study suggest that the releasing of cytochrome c from mitochondria might be involved in the luteal cell apoptosis induced by GnRH-Ag.

• Clinical and Experimental Reproductive Medicine
• /
• v.21 no.1
• /
• pp.121-130
• /
• 1994

Expression of gonadotropin releasing hormone(GnRH) has been described in the rat ovary. It remains, however, unkown whether GnRH is synthesized as a prohormone. Therefore, this study was performed to verify the expression of pro-GnRH by in situ hybridization and further to investigate the effect of gonadotropin on GnRH or GnRH mRNA in rat ovary by immunohistochemical and in situ hybridization techniques. Adult female Sprague-Dawely rats were used and the estrous cycle was synchronized by intraperitoneal injection of pregnant mare's serum gonadotropin(PMSG). Ovaries were fixed with 4% paraformaldehyde and embedded with G.C.T. compound and cut by cryostat. For immunohistochemistry, avidin-biotin peroxidase complex(ABS) method was employed and for in situ hybridization, $^{35}S$-end labeled oligonucleotide was used and followed by autoradiography. By in situ hybridization using GnRH oligomer and GAP(GnRH associated protein) oligomer, GnRH mRNA and GAP mRNA were co-localized in the fullicular cells, luteal cells, interstitial cells and theca cells. GnRH or GnRH mRNA signals in the ovary increased by human chorionic gonadotropin(hCG) injection. At the 3 and 6 hrs after hCG injection, the number of GnRH and GnRH mRNA containing cells increased rapidly and the density of GnRH and GnRH mRHA culminated at 9 hrs after heG injection. With the follicular development, the high expression of GnRH and GnRH mRNA was also observed within the follicles. After ovulation, the density of GnRH or GnRH mRNA decreased in the follicles but increased in the corpus lutea.

• Applied Chemistry for Engineering
• /
• v.17 no.4
• /
• pp.369-374
• /
• 2006

$Rh-Pt/Al_{2}O_{3}$ catalysts were used for the first time to study its reaction characteristics in the asymmetric hydrogenation of ethyl pyruvate. The catalysts were prepared either by impregnation of Rh on a commercial $Pt/Al_{2}O_{3}$ or by sequential impregnation of Rh followed by impregnation of Pt on $Al_{2}O_{3}$. Reaction rate and enantiomeric excess (ee%) were compared according to the preparation method, Rh contents, and the reduction temperature of the catalyst. The physical characteristics of the catalysts were analyzed using XRD and TEM. Bimetallic $Rh-Pt/Al_{2}O_{3}$ catalysts showed an improved reaction rate and optical purity (63.6 ee%) with increasing the reduction temperature. The variation of the Rh contents as well as the preparation method elicited a big difference on the reaction rate, while enantiomeric excess (ee%) was lower (56~60%) with all bimetallic catalysts than with monometallic $Pt/Al_{2}O_{3}$ catalyst.

• Fisheries and Aquatic Sciences
• /
• v.14 no.4
• /
• pp.379-388
• /
• 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.

• Applied Chemistry for Engineering
• /
• v.9 no.4
• /
• pp.554-560
• /
• 1998

Vinylbenzyl triphenyl phosphonium chloride(VTPC)/styrenes=3.7 copolymer was prepared for the moisture-absorptive polyelectrolyte dew sensor containing phosphonium salts. The humid membrane was fabricated on the gold/alumina electrode by dipping. The impedances were $11M{\Omega}$, $980k{\Omega}$, $50k{\Omega}$, and $11k{\Omega}$ at 70%RH, 80%RH, 90%RH and 95%RH, respectively, at $25^{\circ}C$ and the humidity-sensitive charactristic was suitable for the dew sensor. The temperature-dependent coefficient between $15^{\circ}C$ and $35^{\circ}C$ was found to be $-0.25%RH/^{\circ}C$ and the hysteresis falled in the ${\pm}2%RH$ range. The response time was found to be 45 sec for the relative humidity ranging from 70%RH to 98%RH at $25^{\circ}C$. The reliabilities such as temperature cycle, humidity cycle, high temperature and humidity resistance, electrical load stability, stability of long-term storage and water durability were measured and evaluated for the application as a dew sensor.

• Korean Journal of Materials Research
• /
• v.11 no.2
• /
• pp.126-131
• /
• 2001

The mutually reactive copolymers poly[(vinylbenzyl chloride)-co-(n-butyl acrylate)-co-(2-hydroxyethyl methacrylate)] and poly[(4-vinylpyridine)-co-(n-butyl acrylate)-co-(2-hydroxyethyl methacrylate)] were synthesized for the humidity sensitive material by forming simultaneous quaternization. The humidity sensor showed an average resistance of 8.6 M$\Omega$, 310 k$\Omega$ and 12 k$\Omega$ at 30%RH, 60%RH and 90%RH, respectively. The hysteresis and temperature coefficient were $\pm$3%RH and -0.37~-0.40%RH/$^{\circ}C$. The introduction of n-BA and HEMA increased the resistance of the humidity sensor however it enhanced the adherence to the alumina substrate. The response time was 54 seconds changing from 33%RH to 85%RH and the difference of resistance was +0.2%RH after soaking in water for 2 hr.

• The Zoological Society Korea : Newsletter
• /
• v.16 no.1
• /
• pp.17-50
• /
• 1999

시상하부에 극히 적은 수로 존재하는 신경분비세포인 성선자극호르몬-방출호르몬(gonadotropin-releasing hormone; GnRH) 뉴런은인간을 포함한 포유동물의 생식과 발생 과정에 있어 중요한 역할을 담당하고 있다. GnRH 뉴런은 배아 발생과정 중에 후판에서 유래하여 시상하부의 여러 영역으로 이동하며, 생후와 사춘기를 거치면서 분화를 계속한다. GnRH 뉴런에서 합성, 분비되는 10개의 아미노산으로 이루어진 작은 신경호르몬인 GnRH는 맥동적으로 분비되어 뇌하수체 성선자극 세포막에 존재하는 GnRH 수용체와 결합한 후 일련의 신호전달과정을 거쳐 성선자극호르몬의 합성과 분비를 제어하게 된다. GnRH의 합성과 분비는 글루탐산, 노르에피네프린, GABA와 같은 각종 신경입력과 스테로이드 호르몬에 의한 액성 피드백 신호에 의해 조절되나 이들의 GnRH 유전자 발현에 미치는 영향은 최근에 연구되고 있는 실정이다. GnRH 뉴런의 분화와 발생에는 다양한 신경영양인자들이 영향을 미치나 그 분자생물학적 기작은 아직 밝혀져 있지 않다. 본 논단에서는 신경호르몬인 GnRH와 그 수용체에 관하여 최근 연구성과를 중심으로 살펴보고자 한다.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.12
• /
• pp.3600-3604
• /
• 2010

Rhodium(III)-$Cp^*$ complexes containing labile ligands, $[Cp^*RhCl_2]_2$, [$Cp^*Rh({\eta}^2-NO_3)$(OTf)], and $[Cp^*Rh(OH_2)_3](OTf)_2$, reacted with potential linking ligands [$L^1$ = (2-thiophene)-CH=N-N=CH-(2-thiophene); $L^2$ = (2-furan)-CH=N-N=CH-(2-furan)] to give two molecular compounds, [$Cp^*Rh(L^1)Cl_2$] (1) and [$Cp^*Rh({\eta}^2-NO_3)(L^1)$]$(OTf){\cdot}CH_2Cl_2$ ($2{\cdot}CH_2Cl_2$), and one 1-dimensioanl coordination polymer, $\{[Rh(L^2)]{\cdot}(OTf)}_{\infty}$ (3). Whereas one imine nitrogen atom within the ligand is coordinated to the Rh metal in compounds 1 and 2, both nitrogen atoms are bound to two neighboring Rh metals in compound 3 to lead to a 1-D chain polymer.

• Journal of Veterinary Clinics
• /
• v.19 no.3
• /
• pp.322-327
• /
• 2002

The effect of GnRH alone and concomitant with PMSG on the prevention of implantation. termination of pregnancy, and concentration of plasma progesterone were studied in pregnant rats. GnRH 50, 100 or 200 ug alone and concomitant with PMSG 25 or 50 IU were administered once on day 2 or 9 of gestation, respectively. Rats were autopsied on days 7 or 20. Administration of GnRH on day 2 did not result in the prevention of implantation and termination of pregnancy but resulted in termination of pregnancy administering on day 9. Administration of GnRM concomitant with PMSG on day 2 or 9 resulted in prevention of implantation and termination of pregnancy, but injection of GnRH 50 ug concomitant with PMSG 25 IU on day 9 had only one live fetus. Administration of GnRH alone and concomitant with PMSG on day 2 had no effect on the concentration of plasma progesterone determining on day 7. Administration of GnRH concomitant with PMSG on day 2 resulted in decrease of progesterone level determining on day 20 but GnRH alone was normal level. Administration of GnRH alone and concomitant with PMSG on day 9 resulted in decrease of the concentration of progesterone but was normal concentration administering GnRH 50 ug concomitant with PMSG 25 IU.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.12
• /
• pp.1081-1088
• /
• 2009

The performance of a electrocoagulation (EC) process was examined for the removal of Rhodamine B (RhB) using iron electrode. The effects of operational parameters such as electrode material (aluminum and iron), current density, NaCl dosage, intial pH and initial dye concentration on RhB removal efficiency were investigated. The optimum range for each of these operating variables were experimentally determined. The experimental results showed that the iron is superior to aluminum as sacrificial electrode material. The optimum time of electrolysis, current density, NaCl dosage and pH were 10 min, 1630 A/$m^2$, 4 g/L and neutral pH, respectively. Under these conditions, RhB was effectively removed (> 93.4%) and also more than 80% of COD was removed (> 88.9%) when the initial concentration of RhB was 230 mg/L. The electrical energy consumption in the above conditions for the color and COD of RhB removal were 10.3 and 10.8 kWh/kg RhB, respectively. The electrocoagulation process could be a promising technology to treat dye wastewater containing RhB.