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1.
Phys Rev Lett ; 111(11): 115303, 2013 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-24074102

RESUMO

Recently, the possibility of quantum simulation of dynamical gauge fields was pointed out by using a system of cold atoms trapped on each link in an optical lattice. However, to implement exact local gauge invariance, fine-tuning the interaction parameters among atoms is necessary. In the present Letter, we study the effect of violation of the U(1) local gauge invariance by relaxing the fine-tuning of the parameters and showing that a wide variety of cold atoms is still a faithful quantum simulator for a U(1) gauge-Higgs model containing a Higgs field sitting on sites. The clarification of the dynamics of this gauge-Higgs model sheds some light upon various unsolved problems, including the inflation process of the early Universe. We study the phase structure of this model by Monte Carlo simulation and also discuss the atomic characteristics of the Higgs phase in each simulator.

2.
J Pharmacol Exp Ther ; 346(3): 443-52, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23853170

RESUMO

GPR40 is a free fatty acid receptor that has been shown to regulate glucose-dependent insulin secretion. This study aimed to discover novel GPR40 agonists and investigate the whole-body effect on glucose metabolism of GPR40 activation using these novel GPR40 agonists. To identify novel GPR40-specific agonists, we conducted high-throughput chemical compound screening and evaluated glucose-dependent insulin secretion. To investigate the whole-body effect on glucose metabolism of GPR40 activation, we conducted repeat administration of the novel GPR40 agonists to diabetic model ob/ob mice and evaluated metabolic parameters. To characterize the effect of the novel GPR40 agonists more deeply, we conducted an insulin tolerance test and a euglycemic-hyperinsulinemic clamp test. As a result, we discovered the novel GPR40-specific agonists, including AS2034178 [bis{2-[(4-{[4'-(2-hydroxyethoxy)-2'-methyl[1,1'-biphenyl]-3-yl]methoxy}phenyl)methyl]-3,5-dioxo-1,2,4-oxadiazolidin-4-ide} tetrahydrate], and found that its exhibited glucose-dependent insulin secretion enhancement both in vitro and in vivo. In addition, the compounds also decreased plasma glucose and HbA1c levels after repeat administration to ob/ob mice, with favorable oral absorption and pharmacokinetics. Repeat administration of AS2034178 enhanced insulin sensitivity in an insulin tolerance test and a euglycemic-hyperinsulinemic clamp test. These results indicate that improvement of glucose-dependent insulin secretion leads the improvement of whole-body glucose metabolism chronically. In conclusion, AS2034178 and other GPR40 agonists may become useful therapeutics in the treatment of type 2 diabetes mellitus.


Assuntos
Glucose/metabolismo , Insulina/metabolismo , Receptores Acoplados a Proteínas G/agonistas , Animais , Compostos de Bifenilo/farmacologia , Glicemia/metabolismo , Células CHO , Cálcio/metabolismo , Cricetinae , Cricetulus , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , Técnica Clamp de Glucose , Teste de Tolerância a Glucose , Masculino , Camundongos , Camundongos Endogâmicos ICR , Camundongos Obesos , Oxidiazóis/farmacologia , PPAR gama/metabolismo , Ratos , Ratos Zucker , Ativação Transcricional/efeitos dos fármacos
3.
Life Sci ; 92(2): 167-73, 2013 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-23246743

RESUMO

AIMS: G-protein-coupled receptor 119 (GPR119), mainly expressed in pancreatic ß-cells, represents a new target for treating type 2 diabetes. GPR119 agonist is known to induce insulin secretion in a glucose-dependent manner by elevating intracellular cAMP concentrations. This study mainly examined the anti-hyperglycemic effect of a novel candidate small-molecule GPR119 agonist AS1669058 2-(4-bromo-2,5-difluorophenyl)-6-methyl-N-[2-(1-oxidopyridin-3-yl)ethyl]pyrimidin-4-amine ethanedioate on ICR mice and diabetic db/db mice. MAIN METHODS: We measured blood glucose, plasma insulin, and insulin content in the pancreas after repeated administration of AS1669058 to db/db mice twice daily for one week. KEY FINDINGS: Under high-concentration glucose conditions, AS1669058 induced insulin secretion in a dose-dependent manner in the hamster pancreatic ß-cell line HIT-T15 and in rat pancreatic islets. In addition, AS1669058 increased human insulin promoter activity in NIT-1 cells. In in vivo studies, a single administration of AS1669058 (1 mg/kg) in ICR mice improved oral glucose tolerance based on insulin secretion. Further, 1-week repeated treatment (3 mg/kg, twice daily) in diabetic db/db mice significantly reduced blood glucose levels and tended to increase insulin content in the pancreas. SIGNIFICANCE: These results suggest that AS1669058 has promising potential as an extremely more effective anti-hyperglycemic agent than other compounds we previously reported as GPR119 agonists.


Assuntos
Hipoglicemiantes/uso terapêutico , Células Secretoras de Insulina/efeitos dos fármacos , Insulina/metabolismo , Piridinas/uso terapêutico , Pirimidinas/uso terapêutico , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Animais , Glicemia/análise , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Hipoglicemiantes/sangue , Insulina/análise , Insulina/sangue , Secreção de Insulina , Células Secretoras de Insulina/química , Células Secretoras de Insulina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Piridinas/sangue , Pirimidinas/sangue , Ratos , Ratos Sprague-Dawley
4.
Chem Pharm Bull (Tokyo) ; 60(5): 647-58, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22689403

RESUMO

In the search for potent and selective human ß3-adrenergic receptor (AR) agonists as potential drugs for use in treating obesity and non-insulin dependent (type 2) diabetes, a series of N-phenyl-(2-aminothiazol-4-yl)acetamides with phenoxypropanolamine moiety were prepared and their biological activities against human ß3-, ß2-, and ß1-ARs were evaluated. Among these compounds, N-phenyl-(2-phenylaminothiazol-4-yl)acetamide (4 g), N-phenyl-(2-benzylaminothiazol-4-yl)acetamide (4j), and N-phenyl-[2-(3-methoxyphenyl)aminothiazol-4-yl]acetamide (6g) derivatives showed potent agonistic activity against the ß3-AR with functional selectivity over the ß1- and ß2-ARs. In addition, these compounds exhibited significant hypoglycemic activity in a rodent model of diabetes.


Assuntos
Acetamidas/química , Agonistas de Receptores Adrenérgicos beta 3/síntese química , Hipoglicemiantes/síntese química , Fenoxipropanolaminas/química , Receptores Adrenérgicos beta 3/química , Administração Oral , Agonistas de Receptores Adrenérgicos beta 3/química , Agonistas de Receptores Adrenérgicos beta 3/uso terapêutico , Animais , Diabetes Mellitus Tipo 2/tratamento farmacológico , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Humanos , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Masculino , Camundongos , Obesidade/tratamento farmacológico , Receptores Adrenérgicos beta 1/química , Receptores Adrenérgicos beta 1/metabolismo , Receptores Adrenérgicos beta 2/química , Receptores Adrenérgicos beta 2/metabolismo , Receptores Adrenérgicos beta 3/metabolismo
5.
Biochem Biophys Res Commun ; 402(2): 280-5, 2010 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-20937249

RESUMO

G protein-coupled receptor (GPR) 119 is highly expressed in pancreatic ß-cells and enhances the effect of glucose-stimulated insulin secretion (GSIS) on activation. The development of an oral GPR119 agonist that specifically targets the first phase of GSIS represents a promising strategy for the treatment of type 2 diabetes. In the present study, we evaluated the therapeutic potential of a novel small molecule GPR119 agonist, AS1535907, which was modified from the previously identified 2,4,6-tri-substituted pyrimidine core agonist AS1269574. AS1535907 displayed an EC50 value of 4.8 µM in HEK293 cells stably expressing human GPR119 and stimulated insulin secretion in rat islets only under high-glucose (16.8 mM) conditions. In isolated perfused pancreata from normal rats, AS1535907 enhanced the first phase of insulin secretion at 16.8 mM glucose, but had no effect at 2.8mM glucose. In contrast, the sulfonylurea glibenclamide predominantly induced insulin release in the second phase at 16.8 mM glucose and also markedly stimulated insulin secretion at 2.8 mM glucose. In in vivo studies, a single 10 µM administration of AS1535907 to diabetic db/db mice reduced blood glucose levels due to the rapid secretion of insulin secretion following oral glucose loading. These results demonstrate that GPR119 agonist AS1535907 has the ability to stimulate the first phase of GSIS, which is important for preventing the development of postprandial hypoglycemia. In conclusion, the GPR119 agonist AS1535907 induces a more rapid and physiological pattern of insulin release than glibenclamide, and represents a novel strategy for the treatment of type 2 diabetes.


Assuntos
Óxidos N-Cíclicos/farmacologia , Hipoglicemiantes/farmacologia , Insulina/metabolismo , Pâncreas/efeitos dos fármacos , Piridinas/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Animais , Linhagem Celular , Óxidos N-Cíclicos/química , Óxidos N-Cíclicos/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Glucose/metabolismo , Glucose/farmacologia , Teste de Tolerância a Glucose , Humanos , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Técnicas In Vitro , Secreção de Insulina , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Masculino , Camundongos , Pâncreas/metabolismo , Perfusão , Piridinas/química , Piridinas/uso terapêutico , Ratos , Ratos Sprague-Dawley
6.
Biochem Biophys Res Commun ; 400(4): 745-51, 2010 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-20816753

RESUMO

G-protein-coupled receptor (GPR) 119 is involved in glucose-stimulated insulin secretion (GSIS) and represents a promising target for the treatment of type 2 diabetes as it is highly expressed in pancreatic ß-cells. Although a number of oral GPR119 agonists have been developed, their inability to adequately directly preserve ß-cell function limits their effectiveness. Here, we evaluated the therapeutic potential of a novel small-molecule GPR119 agonist, AS1907417, which represents a modified form of a 2,4,6-tri-substituted pyrimidine core agonist, AS1269574, we previously identified. The exposure of HEK293 cells expressing human GPR119, NIT-1 cells expressing human insulin promoter, and the pancreatic ß-cell line MIN-6-B1 to AS1907417, enhanced intracellular cAMP, GSIS, and human insulin promoter activity, respectively. In in vivo experiments involving fasted normal mice, a single dose of AS1907417 improved glucose tolerance, but did not affect plasma glucose or insulin levels. Twice-daily doses of AS1907417 for 4weeks in diabetic db/db, aged db/db mice, ob/ob mice, and Zucker diabetic fatty rats reduced hemoglobin A1c levels by 1.6%, 0.8%, 1.5%, and 0.9%, respectively. In db/db mice, AS1907417 improved plasma glucose, plasma insulin, pancreatic insulin content, lipid profiles, and increased pancreatic insulin and pancreatic and duodenal homeobox 1 (PDX-1) mRNA levels. These data demonstrate that novel GPR119 agonist AS1907417 not only effectively controls glucose levels, but also preserves pancreatic ß-cell function. We therefore propose that AS1907417 represents a new type of antihyperglycemic agent with promising potential for the effective treatment of type 2 diabetes.


Assuntos
Óxidos S-Cíclicos/farmacologia , Citoproteção , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Pirimidinas/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Animais , Óxidos S-Cíclicos/química , Óxidos S-Cíclicos/uso terapêutico , Teste de Tolerância a Glucose , Humanos , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Insulina/genética , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos , Regiões Promotoras Genéticas/efeitos dos fármacos , Pirimidinas/química , Pirimidinas/uso terapêutico , Ratos , Ratos Zucker
7.
Biochem Biophys Res Commun ; 400(3): 437-41, 2010 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-20804735

RESUMO

The G protein-coupled receptor 119 (GPR119) is highly expressed in pancreatic ß-cells. On activation, this receptor enhances the effect of glucose-stimulated insulin secretion (GSIS) via the elevation of intracellular cAMP concentrations. Although GPR119 agonists represent promising oral antidiabetic agents for the treatment of type 2 diabetes therapy, they suffer from the inability to adequately directly preserve ß-cell function. To identify a new structural class of small-molecule GPR119 agonists with both GSIS and the potential to preserve ß-cell function, we screened a library of synthetic compounds and identified a candidate molecule, AS1269574, with a 2,4,6-tri-substituted pyrimidine core. Here, we examined the preliminary in vitro and in vivo effects of AS1269574 on insulin secretion and glucose tolerance. AS1269574 had an EC(50) value of 2.5µM in HEK293 cells transiently expressing human GPR119 and enhanced insulin secretion in the mouse pancreatic ß-cell line MIN-6 only under high-glucose (16.8mM) conditions. This contrasted with the action of the sulfonylurea glibenclamide, which also induced insulin secretion under low-glucose conditions (2.8mM). In in vivo studies, a single administration of AS1269574 to normal mice reduced blood glucose levels after oral glucose loading based on the observed insulin secretion profiles. Significantly, AS1269574 did not affect fed and fasting plasma glucose levels in normal mice. Taken together, these results suggest that AS1269574 represents a novel structural class of small molecule, orally administrable GPR119 agonists with GSIS and promising potential for the treatment of type 2 diabetes.


Assuntos
Etanolaminas/farmacologia , Glucose/farmacologia , Hipoglicemiantes/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Insulina/metabolismo , Pirimidinas/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Animais , Glicemia/efeitos dos fármacos , Linhagem Celular , Etanolaminas/química , Etanolaminas/isolamento & purificação , Jejum , Humanos , Hipoglicemiantes/química , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Pirimidinas/química , Pirimidinas/isolamento & purificação
8.
Chem Pharm Bull (Tokyo) ; 58(4): 533-45, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20410638

RESUMO

In the search for potent and selective human beta3-adrenergic receptor (AR) agonists as potential pharmacotherapies for the treatment of obesity and non-insulin dependent (type II) diabetes, we prepared a novel series of phenylethanolamine derivatives containing acetanilides and evaluated their biological activities at the human beta3-, beta2-, and beta1-ARs. Among these compounds, the 6-amino-2-pyridylacetanilide (36b), 2-amino-5-methylthiazol-4-ylacetanilide (36g), and 5-amino-1,2,4-thiadiazol-3-ylacetanilide (36h) derivatives showed potent agonistic activity at the beta3-AR with functional selectivity over the beta1- and beta2-ARs. In addition, these compounds exhibited significant hypoglycemic activity in a rodent diabetic model.


Assuntos
Agonistas Adrenérgicos/química , Agonistas Adrenérgicos/uso terapêutico , Agonistas de Receptores Adrenérgicos beta 3 , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Fenetilaminas/química , Fenetilaminas/uso terapêutico , Agonistas Adrenérgicos/síntese química , Agonistas Adrenérgicos/farmacologia , Animais , Glicemia/efeitos dos fármacos , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/farmacologia , Masculino , Camundongos , Modelos Moleculares , Conformação Molecular , Fenetilaminas/síntese química , Fenetilaminas/farmacologia , Receptores Adrenérgicos beta 1/metabolismo , Receptores Adrenérgicos beta 2/metabolismo , Receptores Adrenérgicos beta 3/metabolismo
9.
Bioorg Med Chem ; 17(15): 5510-9, 2009 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-19581100

RESUMO

In the search for potent and selective human beta3-adrenergic receptor (AR) agonists as potential drugs for the treatment of obesity and noninsulin-dependent (type II) diabetes, we prepared a novel series of phenoxypropanolamine derivatives containing the thiourea moiety and evaluated their biological activities at human beta3-, beta2-, and beta1-ARs. Among these compounds, 4-nitrophenylthiourea (18i) and 3-methoxyphenylthiourea (18k) derivatives were found to exhibit potent agonistic activity at the beta3-AR, with EC(50) values of 0.10 and 0.16 microM, respectively, and no agonistic activity for either the beta1- or beta2-AR. In addition, they showed significant hypoglycemic activity in a rodent diabetic model.


Assuntos
Agonistas Adrenérgicos/química , Agonistas Adrenérgicos/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Fenoxipropanolaminas/química , Fenoxipropanolaminas/uso terapêutico , Receptores Adrenérgicos beta/metabolismo , Agonistas Adrenérgicos/síntese química , Agonistas Adrenérgicos/farmacologia , Antagonistas de Receptores Adrenérgicos beta 3 , Animais , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/farmacologia , Camundongos , Estrutura Molecular , Obesidade/tratamento farmacológico , Fenoxipropanolaminas/síntese química , Fenoxipropanolaminas/farmacologia , Receptores Adrenérgicos beta 3/metabolismo , Relação Estrutura-Atividade , Tioureia/síntese química , Tioureia/química , Tioureia/farmacologia , Tioureia/uso terapêutico
10.
Bioorg Med Chem ; 17(9): 3283-94, 2009 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-19362005

RESUMO

In the search for potent and selective human beta3-adrenergic receptor (AR) agonists as potential drugs for the treatment of obesity and noninsulin-dependent (type II) diabetes, a novel series of phenoxypropanolamine derivatives containing acetanilides were prepared and their biological activities were evaluated at the human beta3-, beta2-, and beta1-ARs. Several of the analogues (21a, 21b, and 27a) exhibited potent agonistic activity at the beta3-AR. Among the compounds described herein, the N-methyl-1-benzylimidazol-2-ylacetanilide derivative (21b) was found to be the most potent and selective beta3-AR agonist, with an EC(50) value of 0.28 microM and no agonistic activity for either the beta1- or beta2-AR. In addition, 21b showed significant hypoglycemic activity in a rodent diabetic model.


Assuntos
Acetanilidas/síntese química , Acetanilidas/farmacologia , Agonistas de Receptores Adrenérgicos beta 3 , Fenoxipropanolaminas/síntese química , Fenoxipropanolaminas/farmacologia , Acetanilidas/química , Agonistas de Receptores Adrenérgicos beta 1 , Agonistas de Receptores Adrenérgicos beta 2 , Animais , Células CHO , Células Cultivadas , Cricetinae , Cricetulus , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/tratamento farmacológico , Relação Dose-Resposta a Droga , Desenho de Fármacos , Humanos , Masculino , Camundongos , Modelos Moleculares , Conformação Molecular , Fenoxipropanolaminas/química , Ratos , Relação Estrutura-Atividade
11.
Eur J Med Chem ; 44(6): 2533-43, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19232786

RESUMO

In the search for potent and selective human beta3-adrenergic receptor (AR) agonists as potential drugs for the treatment of obesity and noninsulin-dependent (type II) diabetes, a novel series of acetanilide-based analogues were prepared and their biological activities were evaluated at the human beta3-, beta2-, and beta1-ARs. Among these compounds, 2-pyridylacetanilide (2f), pyrimidin-2-ylacetanilide (2u), and pyrazin-2-ylacetanilide (2v) derivatives exhibited potent agonistic activity at the beta3-AR with functional selectivity over the beta1- and beta2-ARs. In particular, compound 2u was found to be the most potent and selective beta3-AR agonist with an EC(50) value of 0.11 microM and no agonistic activity for either the beta1- or beta2-AR. In addition, 2f, 2u, and 2v showed significant hypoglycemic activity in a rodent diabetic model.


Assuntos
Acetanilidas/farmacologia , Agonistas de Receptores Adrenérgicos beta 3 , Desenho de Fármacos , Pirazinas/farmacologia , Piridinas/farmacologia , Pirimidinas/farmacologia , Acetanilidas/síntese química , Acetanilidas/química , Agonistas de Receptores Adrenérgicos beta 1 , Agonistas de Receptores Adrenérgicos beta 2 , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Humanos , Modelos Moleculares , Conformação Molecular , Pirazinas/síntese química , Pirazinas/química , Piridinas/síntese química , Piridinas/química , Pirimidinas/síntese química , Pirimidinas/química , Estereoisomerismo , Relação Estrutura-Atividade
12.
J Pharmacol Exp Ther ; 321(2): 642-7, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17293563

RESUMO

We evaluated the pharmacological characteristics of (R)-2-(2-aminothiazol-4-yl)-4'-{2-[(2-hydroxy-2-phenylethyl)amino]-ethyl} acetanilide (YM178). YM178 increased cyclic AMP accumulation in Chinese hamster ovary (CHO) cells expressing human beta3-adrenoceptor (AR). The half-maximal effective concentration (EC50) value was 22.4 nM. EC50 values of YM178 for human beta1- and beta2-ARs were 10,000 nM or more, respectively. The ratio of intrinsic activities of YM178 versus maximal response induced by isoproterenol (nonselective beta-AR agonist) was 0.8 for human beta3-ARs, 0.1 for human beta1-ARs, and 0.1 for human beta2-ARs. The relaxant effects of YM178 were evaluated in rats and humans bladder strips precontracted with carbachol (CCh) and compared with those of isoproterenol and 4-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazol-2-one hydrochloride (CGP-12177A) (beta3-AR agonist). EC50 values of YM178 and isoproterenol in rat bladder strips precontracted with 10(-6) M CCh were 5.1 and 1.4 microM, respectively, whereas those in human bladder strips precontracted with 10(-7) M CCh were 0.78 and 0.28 microM, respectively. In in vivo study, YM178 at a dose of 3 mg/kg i.v. decreased the frequency of rhythmic bladder contraction induced by intravesical filling with saline without suppressing its amplitude in anesthetized rats. These findings suggest the suitability of YM178 as a therapeutic drug for the treatment of symptoms of overactive bladder such as urinary frequency, urgency, and urge incontinence.


Assuntos
Acetanilidas/farmacologia , Agonistas de Receptores Adrenérgicos beta 3 , Agonistas Adrenérgicos beta/farmacologia , Tiazóis/farmacologia , Bexiga Urinária/efeitos dos fármacos , Animais , Células CHO , Carbacol/farmacologia , Cricetinae , Cricetulus , AMP Cíclico/metabolismo , Humanos , Isoproterenol/farmacologia , Contração Muscular/efeitos dos fármacos , Propanolaminas/farmacologia , Bexiga Urinária/fisiologia
13.
Phys Rev Lett ; 94(21): 211601, 2005 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-16090308

RESUMO

We introduce a 3D compact U(1) lattice gauge theory having nonlocal interactions in the temporal direction, and study its phase structure. The model is relevant for the compact QED3 and strongly correlated electron systems like the t-J model of cuprates. For a power-law decaying long-range interaction, which simulates the effect of gapless matter fields, a second-order phase transition takes place separating the confinement and deconfinement phases. For an exponentially decaying interaction simulating matter fields with gaps, the system exhibits no signals of a second-order transition.

14.
Biochem Biophys Res Commun ; 326(4): 744-51, 2005 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-15607732

RESUMO

A lysophospholipid series, such as lysophosphatidic acid, lysophosphatidylserine, and lysophosphatidylcholine (LPC), is a bioactive lipid mediator with diverse physiological and pathological functions. LPC has been reported to induce insulin secretion from pancreatic beta-cells, however, the precise mechanism has remained elusive to date. Here we show that an orphan G-protein-coupled receptor GPR119 plays a pivotal role in this event. LPC potently enhances insulin secretion in response to high concentrations of glucose in the perfused rat pancreas via stimulation of adenylate cyclase, and dose-dependently induces intracellular cAMP accumulation and insulin secretion in a mouse pancreatic beta-cell line, NIT-1 cells. The Gs-protein-coupled receptor for LPC was identified as GPR119, which is predominantly expressed in the pancreas. GPR119-specific siRNA significantly blocked LPC-induced insulin secretion from NIT-1 cells. Our findings suggest that GPR119, which is a novel endogenous receptor for LPC, is involved in insulin secretion from beta-cells, and is a potential target for anti-diabetic drug development.


Assuntos
Glucose/metabolismo , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Lisofosfatidilcolinas/farmacologia , Receptores Acoplados a Proteínas G/metabolismo , Animais , Linhagem Celular , Relação Dose-Resposta a Droga , Hormônios/metabolismo , Humanos , Técnicas In Vitro , Secreção de Insulina , Masculino , Especificidade de Órgãos , Pâncreas , Ratos , Ratos Wistar , Distribuição Tecidual
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