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1.
Vaccines (Basel) ; 12(3)2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38543893

RESUMO

Various vaccine platforms, including emerging platforms, have been applied in the development of COVID-19 vaccines. Biotechnology startups often lead the development of new medical technologies, whereas major pharmaceutical companies and public institutions have long contributed to vaccine development. In this study, vaccine platforms and developers involved in COVID-19 vaccine development were analyzed, elucidating the trends of vaccine platforms used, the country distribution of the developers, and differences in the profiles of developers by vaccine platform technologies and country. The analysis revealed that conventional, established, and emerging vaccine platforms have been widely used and that older platforms are more advanced in clinical development. It also demonstrated the emergence of China, in addition to the U.S., while many pharmerging countries have been engaged in development. Startups have significantly contributed to the development of viral vector and RNA-based vaccines, suggesting their important role in the application of novel technologies. The major developers differ by country and region. Alliances, including international collaborations, have progressed in late clinical development. Based on these results, future perspectives of pandemic vaccine development and implications for policy and corporate strategies are discussed.

2.
Drug Discov Today ; 29(2): 103866, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38145871

RESUMO

Small- and medium-sized enterprises (SMEs) have significantly boosted innovative drug discovery, whereas large pharmaceutical companies have focused on incremental drug innovation. I explored the evolving role of SMEs in late-entry drug discovery. A comparative analysis of new drugs approved by the US Food and Drug Administration (FDA) during the 2020s with those approved previously revealed that SMEs have expanded their role to late-entry drug discovery while maintaining their contribution to first-in-target drug discovery. I analyzed the characteristics of SMEs responsible for the discovery of late-entry drugs approved during the 2020s, and the modality, market entry timing, and differentiation points of the drugs. I also discuss encompassing opportunities for SMEs, pharmaceutical industry future alliance strategies, and the importance of startup promotion measures.


Assuntos
Indústria Farmacêutica , Empresa de Pequeno Porte , Estados Unidos , Preparações Farmacêuticas , United States Food and Drug Administration , Descoberta de Drogas
3.
Vaccines (Basel) ; 11(12)2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-38140142

RESUMO

New technological platforms, such as mRNA and adenoviral vector vaccines, have been utilized to develop coronavirus disease 2019 (COVID-19) vaccines. These new modalities enable rapid and flexible vaccine design and cost-effective and swift manufacturing, effectively combating pandemics caused by mutating viruses. Innovation ecosystems, including universities, startups, investors, and governments are crucial for developing these cutting-edge technologies. This review summarizes the research and development trajectory of these vaccine technologies, their investments, and the support surrounding them, in addition to the technological details of each technology. In addition, this study examines the importance of an innovation ecosystem in developing novel technologies, comparing it with the case of Japan, which has lagged behind in COVID-19 vaccine development. It also explores the direction of vaccine development in the post-COVID-19 era.

4.
Pharmaceutics ; 15(7)2023 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-37513981

RESUMO

The discovery and development of first-in-class (FIC) drugs are becoming increasingly important due to increasing reimbursement pressure and personalized medication. To investigate the technological trends and origin of FIC drugs, the FIC drugs approved in the U.S. from January 2011 to December 2022 were analyzed. The analysis shows that previous major target families, viz. enzymes, G-protein coupled receptors, transporters, and transcription factors, are no longer considered major in recent years. Instead, the shares of secreted proteins/peptides and mRNAs have continuously increased from 2011-2014 to 2019-2022, suggesting that the target family of FIC drugs has shifted to molecules previously considered challenging as drug targets. Small molecules were predominant in 2011-2014, followed by a large increase in antibody medicines in 2015-2018 and further diversification of antibody medicine modalities in 2019-2022. Nucleic acid medicine has also continuously increased its share, suggesting that diversifying modalities supports the creation of FIC drugs toward challenging target molecules. Over half of FIC drugs were created by small and medium enterprises (SMEs), especially young companies established in the 1990s and 2000s. All SMEs that produced more than one FIC drug approved in 2019-2022 have the strong technological capability in a specific modality. Investment in modality technologies and facilitating mechanisms to translate academic modality technologies to start-ups might be important for enhancing FIC drug development.

5.
Int J Mol Sci ; 24(13)2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37446178

RESUMO

Because there are a limited number of animal models for psychiatric diseases that can be extrapolated to humans, drug repurposing has been actively pursued. This study was aimed at uncovering recent trends in drug repurposing approaches and new technologies that can predict efficacy on humans based on animal models used in psychiatric drug development. Psychiatric drugs that were approved by the FDA between 2002 and 2022 were listed, and the method of how the drug repurposing has been applied was analyzed. Drug repurposing has been increasingly applied to recently approved psychiatric drugs. The development concepts of psychiatric drugs that have been developed through drug repurposing over the past 20 years were found to be divided into six categories: new application exploration, reduction of side effects, improvement of symptom control, improvement of medication compliance, enhancement of drug efficacy, and reduction of drug-drug interactions. All repurposed drugs approved before 2016 used either prodrugs or active metabolites, while all drugs approved in 2021 and beyond used fixed-dose combinations with sophisticated ideas. SmartCube®, which uses artificial intelligence to predict human drug efficacy from animal phenotypes, was developed and produced novel drugs that show clinical efficacy. Well-designed drug repurposing approaches and new technologies for predicting human drug efficacy based off of animal models would contribute to novel psychiatric drug development.


Assuntos
Inteligência Artificial , Transtornos Mentais , Animais , Humanos , Reposicionamento de Medicamentos/métodos
6.
Biol Pharm Bull ; 46(5): 718-724, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37121698

RESUMO

Improving the new drug discovery and development capability of the Japanese pharmaceutical industry, which shows a huge trade deficit, is an urgent issue. To tackle this issue and propose remedies, this study analyzed the originators and characteristics of new drugs approved by the Food and Drug Administration (FDA) from 2017 to 2022 and examined the contributions of Japanese companies. Analysis of the establishment year of the companies that created the approved drugs showed that bio-ventures established in the 1990s and 2000s highly contributed to the creation of the approved drugs in regions other than Japan (particularly in the US), whereas, in Japan, all approved drugs were created by old incumbent pharmaceutical companies. This suggests the presence of an urgent need in Japan to foster start-ups that link scientific discoveries and technologies in academia to drug discovery. The novelty of approved drugs measured by the ratio of first-in-class, orphan drug, and recent drug modalities did not differ between Japan and other countries, suggesting that Japanese pharmaceutical companies follow the technological trends of new drugs. A case analysis of Kyowa Kirin, the Japanese company that created the largest number of the drugs approved by the FDA from 2017 to 2022 among Japanese companies, suggests that focused investment in modality technology development, strengthening collaboration with academia in biology, and the reutilization of small-molecule drug discovery capabilities are important for improving drug discovery productivity.


Assuntos
Descoberta de Drogas , Indústria Farmacêutica , Estados Unidos , Japão , Preparações Farmacêuticas
7.
Pathogens ; 11(12)2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36558803

RESUMO

In mRNA vaccines against COVID-19, a new technology that had never been used for approved drugs was applied and succeeded in rapid clinical use. The development and application of new technologies are critical to solving emerging public health problems therefore it is important to understand which factors enabled the rapid development of the COVID-19 mRNA vaccines. This review discusses administrative and technological aspects of rapid vaccine development. In the technological aspects, I carefully examined the technology and clinical development histories of BioNTech and Moderna by searching their publication, patent application and clinical trials. Compared to the case of Japanese company that has not succeeded in the rapid development of mRNA vaccine, years of in-depth technology research and clinical development experience with other diseases and viruses were found to have enhanced BioNTech and Moderna's technological readiness and contributed to rapid vaccine development against COVID-19 in addition to government administrative support. An aspect of the investments that supported the long-term research and development of mRNA vaccines is also discussed.

8.
ACS Med Chem Lett ; 4(8): 790-4, 2013 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-24900747

RESUMO

GPR142 is a G protein-coupled receptor that is predominantly expressed in pancreatic ß-cells. GPR142 agonists stimulate insulin secretion in the presence of high glucose concentration, so that they could be novel insulin secretagogues with reduced or no risk of hypoglycemia. We report here the optimization of HTS hit compound 1 toward a proof of concept compound 33, which showed potent glucose lowering effects during an oral glucose tolerance test in mice and monkeys.

9.
ACS Med Chem Lett ; 4(9): 829-34, 2013 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-24900757

RESUMO

Herein, we report the lead optimization of amrinone-phenylalanine based GPR142 agonists. Structure-activity relationship studies led to the discovery of aminopyrazole-phenylalanine carboxylic acid 22, which exhibited good agonistic activity, high target selectivity, desirable pharmacokinetic properties, and no cytochrome P450 or hERG liability. Compound 22, together with its orally bioavailable ethyl ester prodrug 23, were found to be suitable for in vivo proof-of-concept studies. Compound 23 displayed good efficacy in a mouse oral glucose tolerance test (OGTT). Compound 22 showed GPR142 dependent stimulation of insulin secretion in isolated mouse islets and demonstrated a statistically significant glucose lowering effect in a mouse model bearing transplanted human islets.

10.
Bioorg Med Chem Lett ; 22(18): 5942-7, 2012 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-22884988

RESUMO

The discovery and initial optimization of a series of phenylalanine based agonists for GPR142 is described. The structure-activity-relationship around the major areas of the molecule was explored to give agonists 90 times more potent than the initial HTS hit in a human GPR142 inositol phosphate accumulation assay. Removal of CYP inhibition by exploration of the pyridine A-ring is also described.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Descoberta de Drogas , Hipoglicemiantes/farmacologia , Fenilalanina/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Animais , Relação Dose-Resposta a Droga , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Microssomos Hepáticos/química , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Fenilalanina/síntese química , Fenilalanina/química , Ratos , Relação Estrutura-Atividade
11.
Bioorg Med Chem Lett ; 22(19): 6218-23, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22926069

RESUMO

GPR142 is a novel GPCR that is predominantly expressed in pancreatic ß-cells. GPR142 agonists potentiate glucose-dependent insulin secretion, and therefore can reduce the risk of hypoglycemia. Optimization of our lead pyridinone-phenylalanine series led to a proof-of-concept compound 22, which showed in vivo efficacy in mice with dose-dependent increase in insulin secretion and a decrease in glucose levels.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/farmacologia , Fenilalanina/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Animais , Glicemia/análise , Relação Dose-Resposta a Droga , Estabilidade de Medicamentos , Teste de Tolerância a Glucose , Células HEK293 , Humanos , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/química , Insulina/sangue , Insulina/metabolismo , Secreção de Insulina , Masculino , Camundongos , Camundongos Endogâmicos , Microssomos/química , Fenilalanina/administração & dosagem , Fenilalanina/química , Ratos , Receptores Acoplados a Proteínas G/metabolismo , Relação Estrutura-Atividade
12.
Biol Pharm Bull ; 34(7): 1094-104, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21720019

RESUMO

Peroxisome proliferator-activated receptor γ (PPARγ; NR1C3) is known as a key regulator of adipocytogenesis and the molecular target of thiazolidinediones (TZDs), also known as antidiabetic agents. Despite the clinical benefits of TZDs, their use is often associated with adverse effects including peripheral edema, congestive heart failure, and weight gain. Here we report the identification and characterization of a non-thiazolidinedione PPARγ partial agonist, Cerco-A, which is a derivative of the natural product, (-)-cercosporamide. Cerco-A was found to be a binder of the PPARγ ligand-binding domain in a ligand competitive binding assay and showed a unique cofactor recruitment profile compared to rosiglitazone. A crystal structure analysis revealed that Cerco-A binds to PPARγ without direct hydrogen bonding to helix12. In PPARγ transcriptional activation assay and an adipocyte differentiation assay, Cerco-A was a potent partial agonist of PPARγ. After a 14-day oral administration, once per day of Cerco-A in Zucker diabetic fatty (ZDF) rats, an apparent decrease of plasma glucose and triglyceride was observed, as with pioglitazone. To evaluate drug safety, Cerco-A was administered for 13 days orally in non-diabetic Zucker fatty (ZF) rats. Each of the hemodilution parameters (hematocrit, red blood cells number, and hemoglobin), which are considered as undesirable effects of TZDs, was improved significantly compared to pioglitazone. While Cerco-A showed body weight gain, as with pioglitazone, Cerco-A had significantly lower effects on heart and white adipose tissues weight gain. The results suggest that Cerco-A offers beneficial effects on glycemic control with attenuated undesirable side effects.


Assuntos
Benzofuranos/farmacologia , PPAR gama/farmacologia , Adipócitos/citologia , Adipócitos/efeitos dos fármacos , Animais , Sequência de Bases , Benzofuranos/administração & dosagem , Benzofuranos/química , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Primers do DNA , Polarização de Fluorescência , Humanos , Ligantes , Estrutura Molecular , PPAR gama/genética , PPAR gama/metabolismo , Ratos , Ratos Zucker
13.
Bioorg Med Chem Lett ; 20(1): 341-5, 2010 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-19926281

RESUMO

Starting from a known piperazine-based SCD-1 inhibitor, we obtained more potent benzoylpiperidine analogs. Optimization of the structure of the benzoylpiperidine-based SCD-1 inhibitors resulted in the identification of 6-[4-(2-methylbenzoyl)piperidin-1-yl]pyridazine-3-carboxylic acid (2-hydroxy-2-pyridin-3-yl-ethyl)amide (24) which showed strong inhibitory activity against both human and murine SCD-1. In addition, this compound exhibited good oral bioavailability and demonstrated plasma triglyceride lowering effects in Zucker fatty rats in a dose-dependent manner after a 7-day oral administration (qd).


Assuntos
Inibidores Enzimáticos/química , Hipoglicemiantes/química , Piperidinas/química , Piridazinas/química , Piridinas/química , Estearoil-CoA Dessaturase/antagonistas & inibidores , Triglicerídeos/sangue , Administração Oral , Animais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacocinética , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/farmacocinética , Camundongos , Microssomos Hepáticos/metabolismo , Piperidinas/síntese química , Piperidinas/farmacocinética , Piridazinas/síntese química , Piridazinas/farmacologia , Piridinas/síntese química , Piridinas/farmacologia , Ratos , Ratos Zucker , Estearoil-CoA Dessaturase/metabolismo
15.
Bioorg Med Chem Lett ; 19(15): 4159-66, 2009 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-19541482

RESUMO

The continuing investigation of SAR studies of 3-(2-hydroxyethoxy)-N-(5-benzylthiazol-2-yl)-benzamides as stearoyl-CoA desaturase-1 (SCD-1) inhibitors is reported. Our prior hit-to-lead effort resulted in the identification of 1a as a potent and orally efficacious SCD-1 inhibitor. Further optimization of the structural motif resulted in the identification of 4-ethylamino-3-(2-hydroxyethoxy)-N-[5-(3-trifluoromethylbenzyl)thiazol-2-yl]benzamide (37c) with sub nano molar IC(50) in both murine and human SCD-1 inhibitory assays. This compound demonstrated a dose-dependent decrease in the plasma desaturation index in C57BL/6J mice on a non-fat diet after 7 days of oral administration.


Assuntos
Benzamidas/síntese química , Química Farmacêutica/métodos , Estearoil-CoA Dessaturase/antagonistas & inibidores , Tiazóis/síntese química , Administração Oral , Animais , Área Sob a Curva , Benzamidas/farmacologia , Relação Dose-Resposta a Droga , Desenho de Fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Humanos , Concentração Inibidora 50 , Camundongos , Camundongos Endogâmicos C57BL , Modelos Químicos , Estearoil-CoA Dessaturase/química , Relação Estrutura-Atividade , Tiazóis/química , Tiazóis/farmacologia
16.
Nucleic Acids Symp Ser (Oxf) ; (51): 111-2, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18029611

RESUMO

The 2'-0-(2-methoxy)ethyl (2'-MOE)-modified gapmer antisense oligonucleotide ISIS113715, which targets protein-tyrosine phosphatase IB (PTP1B) mRNA, increases insulin sensitivity and normalizes plasma glucose levels in diabetic ob/ob and db/db mice. In the present study, the efficacy of the isosequential 2'-O,4'-C-ethylene-bridged nucleic acid (ENA)-modified oligonucleotide ENA-1 was compared with that of ISIS113715 in order to further improve the down-regulation of PTP1B in db/db mice. Intraperitoneal administration of ENA-1 more effectively decreased the plasma glucose levels in db/db mice than ISIS113715. Moreover, ENA-1 decreased the expression of PTP1B in the liver and fat of db/db mice more effectively than ISIS113715. These data indicate that ENA modifications enhance the ability of antisense oligonucleotides and make them superior to second-generation 2'-MOE modifications. We would like to thank to Drs. Shinya Tsutsumi and Kenji Kawai for the T(m) measurement and autoradiography experiments. ENA is a registered trademark of Mitsubishi-Kagaku Foods Corporation.


Assuntos
Glicemia/efeitos dos fármacos , Oligonucleotídeos Antissenso/química , Oligonucleotídeos Antissenso/farmacologia , Oligonucleotídeos/química , Oligonucleotídeos/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Animais , Camundongos , Camundongos Obesos , Oligorribonucleotídeos/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/genética , RNA Mensageiro/metabolismo
17.
Oligonucleotides ; 16(3): 253-62, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16978088

RESUMO

Protein-tyrosine phosphatase 1B (PTP1B) inhibitory activity of the 2'-O-(2-methoxy)ethyl (2'- MOE)-modified gapmer antisense oligonucleotide, ISIS113715, was previously reported. This antisense oligonucleotide increases insulin sensitivity and normalizes plasma glucose levels in diabetic ob/ob and db/db mice. In the present study, the isosequential 2'-O,4'-C-ethylene-bridged nucleic acid (ENA)-modified oligonucleotide, ENA-1, was synthesized, and its ability to further improve the downregulation of PTP1B in db/db mice was examined. We demonstrated that, compared with ISIS113715, intraperitoneal and subcutaneous administration of ENA-1 more effectively decreased the plasma glucose levels in db/db mice. Moreover, ENA-1 decreased expression of PTP1B in the liver and fat of db/db mice more effectively than ISIS113715. We describe for the first time the functional comparison of 2'-MOE- and ENA-modified antisense oligonucleotides. Our data indicate that the enhancement of the efficacy of antisense oligonucleotides by ENA modifications is superior to that of second-generation 2'-MOE modifications in certain aspects.


Assuntos
Oligonucleotídeos Antissenso/metabolismo , Proteínas Tirosina Fosfatases/genética , RNA Antissenso/fisiologia , RNA Mensageiro/metabolismo , Animais , Temperatura Alta , Masculino , Camundongos , Oligorribonucleotídeos , Proteína Tirosina Fosfatase não Receptora Tipo 1 , Receptores de Superfície Celular/genética , Receptores para Leptina
18.
Biochem Biophys Res Commun ; 332(1): 263-70, 2005 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-15896326

RESUMO

To estimate the turnover of UDP-N-acetylglucosaminyl transferase (OGT), we exposed stably transfected HeLa cells to tetracycline for 16h to induce OGT gene expression and increase cytosolic enzyme levels. Removal of tetracycline led to a progressive decrease in OGT activity (after a 6h lag period), yielding an estimated OGT half-life of 13h. A similar half-life (12h) was obtained by measuring the loss of biosynthetically labeled OGT ([35S]methionine pulse-chase experiments). Since OGT turnover was relatively slow, it is unlikely that changes in OGT gene expression or protein expression play a role in the short-term regulatory actions mediated by the hexosamine signaling pathway. We also found that the overexpressed 110kDa murine OGT subunit (recombinant enzyme) was enzymatically similar to the endogenous holoenzyme derived from rat brain tissue. Thus, stably transfected HeLa cells provide an abundant source of enzyme that can be used to study the structure, function, and regulation of OGT.


Assuntos
Regulação Enzimológica da Expressão Gênica , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/metabolismo , Transfecção/métodos , Células HeLa , Humanos , Taxa de Depuração Metabólica , Transdução de Sinais
19.
Anal Chem ; 77(7): 2050-5, 2005 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-15801737

RESUMO

We show an efficient method to identify molecular targets of small molecular compounds by affinity purification and mass spectrometry. Binding proteins were isolated from target cell lysate using affinity columns, which immobilized the active and inactive compounds. All proteins bound to these affinity columns were eluted by digestion using trypsin and then were identified by mass spectrometry. The specific binding proteins to the active compound, a candidate for molecular targets, were determined by subtracting the identified proteins in an inactive compound-immobilized affinity column from that in an active compound-immobilized affinity column. This method was applied to identification of molecular targets of D942, a furancarboxylic acid derivative, which increases glucose uptake in L6 myocytes through AMP-activated protein kinase (AMPK) activation. To elucidate the mechanism of AMPK activation by D942, affinity columns that immobilized D942 and its inactive derivative, D768, were prepared, and the binding proteins were purified from L6 cell lysate. NAD(P)H dehydrogenase [quinone] 1 (complex I), which was shown as one of the specific binding proteins to D942 by subtracting the binding proteins to D768, was partially inhibited by D942, not D768. Because inhibition of complex I activity led to a decrease in the ATP/AMP ratio, and the change in the ATP/AMP ratio triggered AMPK activation, we identified complex I as a potential protein target of AMPK activation by D942. This result shows our approach can provide crucial information about the molecular targets of small molecular compounds, especially target proteins not yet identified.


Assuntos
Cromatografia de Afinidade/métodos , Espectrometria de Massas/métodos , Mapeamento de Interação de Proteínas/métodos , Proteínas Quinases/metabolismo , Quinases Proteína-Quinases Ativadas por AMP , Animais , Glicemia/análise , Ácidos Carboxílicos/farmacologia , Linhagem Celular , Complexo I de Transporte de Elétrons/efeitos dos fármacos , Complexo I de Transporte de Elétrons/metabolismo , Ativação Enzimática , Feminino , Furanos/farmacologia , Células Musculares/citologia , Células Musculares/metabolismo , Proteínas Quinases/análise , Ratos , Ratos Zucker
20.
Biochem Biophys Res Commun ; 329(3): 1155-61, 2005 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-15752775

RESUMO

We have examined the hypothesis that glucosamine (GlcN) can rapidly induce insulin resistance through an allosteric mechanism. When insulin-treated adipocytes were exposed to 2mM GlcN, glucose uptake was rapidly reduced by approximately 60% with a T(1/2) of 2 min. We also observed an increase in intracellular GlcN-6-P (at 5 min) from undetectable levels to approximately 260 nmol/g. Continued GlcN treatment resulted in additional accumulation of GlcN-6-P (>1200 nmol/g at 2h), but caused no further decrease in glucose uptake. Although the acute inhibitory action of GlcN could be completely reversed by removing extracellular GlcN, a slow and progressive decrease in insulin-stimulated glucose transport was observed with longer treatment times (T(1/2) of 45 min, 62% loss by 5h). From these data, we conclude that: (1) GlcN elevates intracellular GlcN-6-P levels within minutes, resulting in desensitization of the glucose transport system through allosteric inhibition of hexokinase; (2) prolonged treatment elevates GlcN-6-P to levels that cannot be effectively lowered by cell washing; and (3) residual levels of GlcN-6-P continue to allosterically inhibit glucose uptake, resulting in a slower rate of desensitization that is temporally similar to glucose-induced desensitization, but mechanistically different.


Assuntos
Adipócitos/metabolismo , Glucosamina/análogos & derivados , Glucosamina/metabolismo , Glucosamina/farmacologia , Glucose-6-Fosfato/análogos & derivados , Glucose-6-Fosfato/metabolismo , Glucose/farmacocinética , Resistência à Insulina/fisiologia , Insulina/farmacologia , Adipócitos/efeitos dos fármacos , Animais , Transporte Biológico Ativo/efeitos dos fármacos , Transporte Biológico Ativo/fisiologia , Células Cultivadas , Relação Dose-Resposta a Droga , Masculino , Taxa de Depuração Metabólica , Ratos , Ratos Sprague-Dawley
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