• Title/Summary/Keyword: Agonist

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The Synergistic Effect of Additional Ethanol Exposure on Quercetin-induced Vasorelaxation in a Vasoconstrictor-dependent Manner (Quercetin에 의한 혈관이완효과에 대한 알코올의 추가적인 역할)

  • Jin, Young-Bae;Je, Hyun-Dong
    • YAKHAK HOEJI
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    • v.54 no.5
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    • pp.392-397
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    • 2010
  • The aim of present study was to investigate the possible influence and related mechanism of additional alcohol on the flavonoid- induced arterial relaxation. Agonist-induced vascular smooth muscle contractions involve the activation of thick or thin filament pathway. However, there are no reports addressing the question whether this pathway is involved in quercetin-induced relaxation cotreated with alcohol in rat aortae contracted with phorbol ester, fluoride or thromboxane $A_2$ mimetic U-46619. We hypothesized that cotreated alcohol plays a role in vascular relaxation evoked by quercetin in rat aortae. Endothelium-denuded arterial rings from male Sprague-Dawley rats were used and isometric contractions were recorded using a computerized data acquisition system. Quercetin inhibited phorbol ester, fluoride or thromboxane $A_2$-induced contraction regardless of endothelial function. However, alcohol didn't decrease any agonist-induced contraction. Interestingly, only in thromboxane $A_2$-induced contraction, synergistic results were observed in aortae denuded and cotreated with quercetin and alcohol suggesting that additional pathways different from antioxidation or endothelial nitric oxide synthesis might be involved in the vasorelaxation. In conclusion, in the agonists-contracted rat aortae, quercetin and alcohol together showed synergistic response regardless of endothelial function in an agonist-dependent manner.

The Effect of Contract-Relax with Agonist Contraction on Hamstring Extensibility in Normal Subjects (무릎굽힘근의 신장성에 대한 수축-이완 기술의 효과)

  • Song, Eun-Ji;Oh, Sung-Hee;Lee, Seung-Hwa;Yi, Chung-Hwi
    • Physical Therapy Korea
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    • v.1 no.1
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    • pp.55-60
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    • 1994
  • Thirty healthy adults aged 20 to 29 with no history of musculoskeletal or neurogenic disorder volunteered for this study. The contract-relax with agonist contration(CRAC) was applied to the right hamstring muscles with the subject in the supine position. Each hamstring group was stretched on three sucessive days with several repetitions of the technique lasting 1min, 3min, and 5min. respectively. Hamstring extensibility at the knee(ROM) was measured before and after stretching using on electronic digital inclinometer(EDI). The results, namely the increase in ROM, were analysed using one-way repeated ANOVA at p<0.05. The differences were not significant. Possible factors influencing the results are excessive sensitibility of the measuring instrument, the psychological and physical status of the subjects, and the level of muscle fatigue. The mean increases in ROM were 3.0 at 1min., 2.6 at 3min, and 2.1 at 5min. Inclusion of a control group would have further defined the effects of the stretching technique.

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The Inhibitory Effect of Quercetin on the Agonist-Induced Regulation of Vascular Contractility

  • Je, Hyun-Dong;Jeong, Ji-Hoon;La, Hyen-Oh
    • Biomolecules & Therapeutics
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    • v.19 no.4
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    • pp.460-465
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    • 2011
  • The present study was undertaken to investigate the influence of quercetin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Quercetin at a low concentration (0.01-0.03 mM) directly and more significantly relaxed fluoride or thromboxane $A_2$-induced vascular contraction than phorbol ester-induced contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, quercetin more significantly inhibited thromboxane $A_2$-induced increases in pMYPT1 levels than phorbol ester-induced increases. It also more significantly inhibited thromboxane $A_2$-induced increases in pMYPT1 levels than pERK1/2 levels suggesting the mechanism involving the primarily inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1. This study provides evidence regarding the mechanism underlying the relaxation effect of quercetin on agonist-induced vascular contraction regardless of endothelial function.

Controversial Effect of Ethanol Irrespective of Kinases Inhibition on the Agonist-Dependant Vasoconstriction

  • Je, Hyun-Dong;Kim, Hyeong-Dong;Park, June-Hong
    • Biomolecules & Therapeutics
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    • v.20 no.3
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    • pp.352-356
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    • 2012
  • The present study was undertaken to determine whether ethanol influences on the agonist-induced vascular smooth muscle contraction and, if so, to investigate the related mechanism. The measurement of isometric contractions using a computerized data acquisition system was combined with molecular experiments. Ethanol significantly inhibited thromboxane $A_2$ mimetic-induced contraction with intact endothelial function, but there was no relaxation on thromboxane $A_2$ mimetic U-46619-induced contraction irrespective of endothelium suggesting that the pathway such as Rho-kinase activation, $Ca^{2+}$ entry or thin filament regulation was not affected. In addition, ethanol didn't decrease thromboxane $A_2$ mimetic-induced increase of phospho-myosin phosphatase targeting subunit protein 1 (pMYPT1) or pERK1/2. Interestingly, ethanol didn't inhibit significantly phorbol ester-induced contraction in denuded muscles suggesting that thin filament regulation is less important on the ethanol-induced regulation in the muscle than endothelial NO synthesis. In conclusion, this study provides the evidence and possible related mechanism concerning the effect of ethanol on the agonist-dependent contraction in rat aortic rings with regard to endothelial function.

Lodoxamide Attenuates Hepatic Fibrosis in Mice: Involvement of GPR35

  • Kim, Mi-Jeong;Park, Soo-Jin;Nam, So-Yeon;Im, Dong-Soon
    • Biomolecules & Therapeutics
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    • v.28 no.1
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    • pp.92-97
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    • 2020
  • A previous pharmacogenomic analysis identified cromolyn, an anti-allergic drug, as an effective anti-fibrotic agent that acts on hepatocytes and stellate cells. Furthermore, cromolyn was shown to be a G protein-coupled receptor 35 (GPR35) agonist. However, it has not been studied whether anti-fibrotic effects are mediated by GPR35. Therefore, in this study, the role of GPR35 in hepatic fibrosis was investigated through the use of lodoxamide, another anti-allergic drug and a potent GPR35 agonist. Long-term treatment with carbon tetrachloride induced hepatic fibrosis, which was inhibited by treatment with lodoxamide. Furthermore, CID2745687, a specific GPR35 antagonist, reversed lodoxamide-mediated anti-fibrotic effects. In addition, lodoxamide treatment showed significant effects on the mRNA expression of collagen Iα1, collagen Iα2, and TGF-β1 in the extracellular matrix. However, a transforming growth factor α (TGF-α) shedding assay revealed lodoxamide not to be a potent agonist of mouse GPR35 in vitro. Therefore, these results showed anti-fibrotic effects of lodoxamide in mice and raise concerns how lodoxamide protects against liver fibrosis in vivo and whether GPR35 is involved in the action.

Pristimerin Inhibits Inducible Nitric Oxide Synthase Expression Induced by TLR Agonists

  • Kim, Su-Yeon;Heo, Sung-Hye;Park, Sin-Aye;Youn, Hyung-Sun
    • Biomedical Science Letters
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    • v.25 no.1
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    • pp.60-65
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    • 2019
  • Toll-like receptors (TLRs) are one of the families of pattern recognition receptors (PRR) operating in the innate immunity. TLRs have the ability to recognize relatively conserved microbial components, which are generally referred to as pathogen-associated molecular patterns (PAMPs). The activation of TLRs signaling leads to the activation of $NF-{\kappa}B$ and the expression of pro-inflammatory gene products such as cytokines and inducible nitric oxide synthase (iNOS). To evaluate the therapeutic potential of pristimerin, which is a naturally occurring triterpenoid compound from Celastraceae plants, iNOS expression induced by MALP-2 (TLR2 and TLR6 agonist), Poly[I:C] (TLR3 agonist), or LPS (TLR4 agonist) were examined. Pristimerin suppressed the iNOS expression induced by MALP-2, Poly[I:C], or LPS. These results suggest that pristimerin can modulate TLRs signaling pathways leading to decreased inflammatory gene expression.

Dehydrocostus Lactone Suppresses the Expression of iNOS Induced by TLR Agonists

  • Kim, Su Yeon;Heo, Sunghye;Kim, Seung Han;Kwon, Minji;Park, Sin-Aye;Youn, Hyung-Sun
    • Biomedical Science Letters
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    • v.25 no.3
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    • pp.267-274
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    • 2019
  • Toll-like receptors (TLRs) are one of the families of pattern recognition receptors (PRR) to recognize pathogen-associated molecular patterns (PAMPs). PAMPs stimulate TLRs to initiate specific immunoactivity. The activation of TLRs signaling leads to the expression of pro-inflammatory gene products such as cytokines and inducible nitric oxide synthase (iNOS). To evaluate the therapeutic potential of dehydrocostus lactone (DHL), which is a natural sesquiterpene lactone derived from various medicinal plants, iNOS expression induced by LPS (TLR4 agonist), MALP-2 (TLR2 and TLR6 agonist), or Poly[I:C] (TLR3 agonist) were examined. DHL suppressed the iNOS expression induced by LPS, MALP-2, or Poly[I:C]. DHL also inhibited nitrite production induced by LPS, MALP-2, or Poly[I:C]. These results suggest that DHL can modulate TLRs signaling pathways resulting in anti-inflammatory effect.

Exercise-induced beige adipogenesis of iWAT in Cidea reporter mice

  • Kim, Jin Kyung;Go, Hye Sun;Kim, Sol Pin;Kim, Il Yong;Lee, Yun Hee;Oh, Seung Hyun;Lee, Ho;Seong, Je Kyung
    • BMB Reports
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    • v.55 no.4
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    • pp.187-191
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    • 2022
  • Obesity is caused by an imbalance between energy intake and energy expenditure. Exercise is attracting attention as one of the ways to treat obesity. Exercise induces 'beige adipogenesis' in white adipose tissue, increasing total energy expenditure via energy dissipation in the form of heat. Also, beige adipogenesis can be induced by treatment with a beta-adrenergic receptor agonist. We developed a Cidea-dual reporter mouse (Cidea-P2A-Luc2-T2A-tdTomato, Luciferase/tdTomato) model to trace and measure beige adipogenesis in vivo. As a result, both exercise and injection of beta-adrenergic receptor agonist induced beige adipogenesis and was detected through fluorescence and luminescence. We confirmed that exercise and beta-adrenergic receptor agonist induce beige adipogenesis in Cidea-dual reporter mouse, which will be widely used for detecting beige adipogenesis in vivo.

The Efficacy of a Combination Administration of GnRH Agonist(Lupron) and Gonadotropins for Controlled Ovarian Hyperstimulation in IVF Program (체외수정시술을 위한 과배란유도시 GnRH Agonist(Lupron)와 성선자극호르몬 복합 투여의 효용성에 관한 연구)

  • Moon, Shin-Yong;Lee, Jin-Yong;Chang, Yoon-Seok
    • Clinical and Experimental Reproductive Medicine
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    • v.17 no.1
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    • pp.29-44
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    • 1990
  • In 105 patients with the past history of poor response to the previous controlled ovarian hyperstimulation(COH) due to poor follicular growth or premature LH surge, the effectiveness of pituitary suppression with gonadotropin-releasing hormone agonist(GnRH agonist) in IVF/GIFT program was evaluated in 112 cycles of COH using a combination regimen of Leuprolide acetate (Lupron TAP Pharmaceuticals, USA) and FSH/hMG or pure FSH from May to December, 1989 at SNUH. Starting on day 21 of the menstrual cycle(MCD #21, Day 1), Lupron (1.0mg/day, subcutaneous) was administered once a day till next MCD #3(suppression phase). After the confirmation of pituitary suppression, ovarian follicular growth was stimulated with FSH/hMG or pure FSH from MCD #3(Day + 1), and Lupron was continued with hMG or FSH until hCG administration (D 0) (stimulation phase). After suppression phase, serum E2 level decreased from 183.7${\pm}$95.1(Day 1) to 17.4${\pm}$12.3pg/ml (Day +1), and serum progesterone level from 19.17${\pm}$8.67 to 0.12${\pm}$0.05ng/ml. But there was no decresas in serum LH and FSH levels; LH from 12.74${\pm}$6.21 to 15.49${\pm}$4.93mIU/ml,FSH from 7.60${\pm}$3.84 to 8.58${\pm}$3.15 rnlU/ml. There was no occurrence of premature LH surge during COH. Eleven cycles(9.8%) were cancelled due to poor follicular growth during stimulation phase, and 3 cycles (3.0%) failed in the transvaginal oocytes fretrieval. Serum E2 level was 1366.8${\pm}$642.4 on D 0 and 1492.3${\pm}$906.9pg/ml on D+1. 7.00${\pm}$3.32 follicles(FD${\geq}$12mm) were observed on D 0, and 6.11${\pm}$4.15 oocytes were retrieved, with the oocyte retrieval rate per follicle of 95.0%. 3.59${\pm}$2.57 oocytes were fertilized and cleaved with the oocyte cleavage rate of 55.7%. In 83 IVF patients, 4.08${\pm}$2.39 embryos were transferred, and 16 pregnancies were obtained with the pregnancy rate per ET 2.39 mebryos were transferred, and 16 pregnancies were obtained with the pregnancy rate per ET of 19.3%. In 6 GIFT patients, 7.83${\pm}$3.31 oocytes were retrieved and transferred with maximum number of 6, but no pregnancy was obtained. When compared with the previous 108 cycles of COH using FSH/hMG or pure FSH regimen, the cancellation rate during COH was significantly decreased, and all the parameters of the outcome of COH including the pregnancy rate were increased. These data suggest that GnRH agonist therapy for pituitary suppression is an effective adjunct to the current gonadotropin regimens for COH in IVF/GIFT and can increase the probability of oocytes retrieval and pregnancy, especially in the previous poor responders.

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Treatment of Uterine Myoma as a Cause of infertility, with a Delayed-Release Formulation of a Gonadotropin-Releasing Hormone Agonist(D-$Trp^6$-LHRH) (불임의 원인으로서의 자궁근종 치료에 있어 GnRH agonist (D-$Trp^6$-LHRH)의 효용에 관한 연구)

  • Park, Sae-Chul;Kwon, Kyung-Ik;Nam, Dong-Ho;Lee, Min-Yong;Lim, Chun-Kun;Yang, Sook-Kyung;Choi, Jong-Moo;Lee, Du-Ryong
    • Clinical and Experimental Reproductive Medicine
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    • v.21 no.1
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    • pp.43-48
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    • 1994
  • To evaluate the effectiveness of GnRH agonist for the treatment of uterine myoma as a cause of infertility, fourteen women were recruited to the study. The patients were treated with a delayed-release formulation of D-$Trp^6$-LHRH in biodegradable microcapsules(Decapeptyl-CR), administered intramuscularly at four week intervals for a period of six monthes. The first injection was given on day 21 of the cycle. Serum estradiol levels fell significantly to the mean value of 257.7pgjml 4 weeks after the first injection. Eleven patients in fourteen treated patients had a reduction in the size of uterine myoma as assessed by ultrasonography, two patients had no change of size and one patient had a increase of size. After the first or second injection, all patients became amenorrheic, then resumption of menstruation ocurred at 12 to 14 weeks after the last injection. Common side effects were hot flush, sweating and dyspareunia, whitch were acceptale. In Eleven patients who had a reduction in the size of uterine myoma by treatment with a delayed- release formulation of D-$Trp^6$-LHRH(Decapeptyl-CR), after above treatment with GnRH agonist, then four patients were treated with myomectomy, three patients had pregnancy and full term delivered by Cesarean section. These data suggest that administration of a delayed-release formulation of a GnRH agonist can be a worthwhile and convenient approach to the medical treatment of uterine myoma as a cause of infertility.

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