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Carbó R, Rodríguez E. Relevance of Sugar Transport across the Cell Membrane. Int J Mol Sci 2023; 24:ijms24076085. [PMID: 37047055 PMCID: PMC10094530 DOI: 10.3390/ijms24076085] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Sugar transport through the plasma membrane is one of the most critical events in the cellular transport of nutrients; for example, glucose has a central role in cellular metabolism and homeostasis. The way sugars enter the cell involves complex systems. Diverse protein systems participate in the membrane traffic of the sugars from the extracellular side to the cytoplasmic side. This diversity makes the phenomenon highly regulated and modulated to satisfy the different needs of each cell line. The beautiful thing about this process is how evolutionary processes have diversified a single function: to move glucose into the cell. The deregulation of these entrance systems causes some diseases. Hence, it is necessary to study them and search for a way to correct the alterations and utilize these mechanisms to promote health. This review will highlight the various mechanisms for importing the valuable sugars needed to create cellular homeostasis and survival in all kinds of cells.
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Affiliation(s)
- Roxana Carbó
- Cardiovascular Biomedicine Department, Instituto Nacional de Cardiología Ignacio Chávez, Juan Badiano #1, Col. Sección XVI, Tlalpan, Mexico City 14080, Mexico
- Correspondence: ; Tel.: +52-55557-32911 (ext. 25704)
| | - Emma Rodríguez
- Cardiology Laboratory at Translational Research Unit UNAM-INC, Instituto Nacional de Cardiología Ignacio Chávez, Juan Badiano #1, Col. Sección XVI, Tlalpan, Mexico City 14080, Mexico;
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Correia RR, Batista VRG, Veras ASC, Tavares MEDA, Souza FLA, Pacagnelli FL, Campos DHS, Giometti IC, Teixeira GR. High-intensity interval training attenuates the effects caused by arterial hypertension in the ventral prostate. Prostate 2022; 82:373-387. [PMID: 34905633 DOI: 10.1002/pros.24285] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/01/2021] [Accepted: 12/03/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND The prostatic effects induced by arterial hypertension is very controversial and its mechanism is unclear. High-intensity interval training (HIIT) is an exercise considered to be hypotensive. The objective of this work was to investigate the molecular, biochemical, and morphological effects of 8 weeks of HIIT in the prostatic tissue of spontaneously hypertensive rats (SHR). METHODS Twenty male SHR rats, 51.4 weeks old, were used. The SHR animals were divided into two groups: spontaneously sedentary hypertensive and spontaneously hypertensive submitted to HIIT. We analyze androgens receptor and glucocorticoid receptors in the prostate. Still, we verify effects of the hypertension and HIIT on the physiopathology prostatic, for immunohistochemistry investigated BCL-2, BAX, IGF-1, FAS/CD95, data's inflammatory tumour necrosis factor α, nuclear factor kappa B and interleukin (IL)-6, anti-inflammatory IL-10. The echocardiographic evaluation was performed at the baseline and after the training period. RESULTS Arterial hypertension promote high prostatic intraepithelial neoplasia incidence in the prostate, increases IGF-1, BCL-2 (p < 0.05), and inflammatory proteins (p < 0.05). Eight weeks of HIIT training reduced the arterial pressure and increase the concentration of tissue collagen and intracellular glycogen and showed a higher expression of BAX, FAS/CD95, and IL-10 proteins (p < 0.05), coinciding with a lower incidence of lesions and lower prostate weight (p < 0.05) and reduction of the BCL-2 and IGF-1. CONCLUSION Our data suggested that arterial hypertension suppressed apoptosis and increased damage prostatic. On other hand, HIIT promotes morphology and function improves in the prostatic environment, inhibited inflammation, and increased apoptosis.
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Affiliation(s)
- Rafael Ribeiro Correia
- Department of Physical Education, Experimental Laboratory of Exercise Biology (LEBioEx), School of Technology and Sciences, São Paulo State University (UNESP), Presidente Prudente, São Paulo, Brazil
| | - Victor Rogério Garcia Batista
- Department of Physical Education, Experimental Laboratory of Exercise Biology (LEBioEx), School of Technology and Sciences, São Paulo State University (UNESP), Presidente Prudente, São Paulo, Brazil
| | - Allice Santos Cruz Veras
- Department of Physical Education, Experimental Laboratory of Exercise Biology (LEBioEx), School of Technology and Sciences, São Paulo State University (UNESP), Presidente Prudente, São Paulo, Brazil
- Multicentric Program of Postgraduate in Physiological Sciences, School of Dentistry of Araçatuba, São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil
| | - Maria Eduarda de Almeida Tavares
- Department of Physical Education, Experimental Laboratory of Exercise Biology (LEBioEx), School of Technology and Sciences, São Paulo State University (UNESP), Presidente Prudente, São Paulo, Brazil
- Multicentric Program of Postgraduate in Physiological Sciences, School of Dentistry of Araçatuba, São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil
| | | | - Francis Lopes Pacagnelli
- Postgraduate Animal Science Program, University of Western São Paulo (UNOESTE), Presidente Prudente, São Paulo, Brazil
| | - Dijon Henrique Salomé Campos
- Department of Clinical Medicine, Botucatu Medical School, São Paulo State University, Botucatu, São Paulo, Brazil
| | - Ines Cristina Giometti
- Department of Reproduction, Faculty of Agricultural Sciences, University of Western São Paulo (UNOESTE), Presidente Prudente, São Paulo, Brazil
| | - Giovana Rampazzo Teixeira
- Department of Physical Education, Experimental Laboratory of Exercise Biology (LEBioEx), School of Technology and Sciences, São Paulo State University (UNESP), Presidente Prudente, São Paulo, Brazil
- Multicentric Program of Postgraduate in Physiological Sciences, School of Dentistry of Araçatuba, São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil
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Voluntary Running Improves In Vivo Insulin Resistance in High-Salt Diet–Fed Rats. Exp Biol Med (Maywood) 2016; 232:1330-7. [DOI: 10.3181/0704-rm-107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
It is well known that exercise training, including voluntary running (VR), improves insulin resistance. However, the effect of VR on insulin resistance induced by high salt intake is unclear. The aim of this study was to determine whether VR would improve the glucose utilization in normal male Sprague-Dawley rats fed a high-salt diet (HSD) on 2-week early prevention and 1-week midway intervention protocols. In vivo glucose utilization was measured by euglycemic clamp technique. Further analyses of the possible changes in insulin signaling occurring in skeletal muscle were performed by Western blot and reverse transcription polymerase chain reaction (RT-PCR). The glucose infusion rates (GIRs) after 2 weeks of HSD feeding were decreased (HSD vs. control: 21.5 ± 0.8 vs. 27 ± 0.5 mg/kg body wt/min; P < 0.05), and improved by 2 weeks VR to 30.5 ± 1.5 mg/kg body wt/min. Additionally, the GIRs after 3 weeks of HSD feeding were decreased (HSD vs. control: 20.0 ± 0.3 vs. 26.5 ± 0.6 mg/kg body wt/min; P < 0.05), and they also improved by the third week of VR (28.5 ± 0.7 mg/ kg body wt/min vs. sedentary; P < 0.01). There were no differences in skeletal muscle for the total mass of insulin receptor-beta (IR-β), IR substrate-1 (IRS-1), Akt, and glucose transporter 4 (GLUT4) in any of the groups of 2 weeks of HSD loading control and VR. VR did not regulate the enhanced tyrosine phosphorylation of IR-β and IRS-1 by 2 weeks of HSD feeding. However, the enhanced serine phosphorylation of Akt and the tyrosine phosphorylation of GLUT4 were significantly inhibited by the early VR. HSD also impaired GLUT4 content in the plasma membrane and mRNA expression, but the decreases were improved by 2 weeks of VR. These results suggest that early voluntary exercise would prevent the development of insulin resistance induced by an HSD due in part by enhancing the impaired GLUT4 translocation and mRNA expression in skeletal muscle.
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Long L, Wu S, Sun J, Wang J, Zhang H, Qi G. Effects of octacosanol extracted from rice bran on blood hormone levels and gene expressions of glucose transporter protein-4 and adenosine monophosphate protein kinase in weaning piglets. ACTA ACUST UNITED AC 2015; 1:293-298. [PMID: 29767050 PMCID: PMC5940994 DOI: 10.1016/j.aninu.2015.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 12/16/2015] [Indexed: 01/16/2023]
Abstract
The object of this study was to explore the regulatory mechanism of octacosanol to the body of animals and the effects of octacosanol on blood hormone levels and gene expressions of glucose transporter protein (GLUT-4) and adenosine monophosphate protein kinase (AMPK) in liver and muscle tissue of weaning piglets. A total of 105 crossbred piglets ([Yorkshire × Landrace] × Duroc) with an initial BW of 5.70 ± 1.41 kg (21 d of age) were used in a 6-wk trial to evaluate the effects of octacosanol and tiamulin supplementation on contents of triiodothyronine (T3), thyroxine (T4), growth hormone (GH), glucagon (GU) and adrenaline (AD) in blood and gene expressions of GLUT-4 and AMPK in liver and muscle. Piglets were randomly distributed into 3 dietary treatments on the basis of BW and sex. Each treatment had 7 replicate pens with 5 piglets per pen. Treatments were as followed: control group, tiamulin group and octacosanol group. The results showed that compared with control group and tiamulin group, octacosanol greatly promoted the secretion of T3, GH, GU and AD (P < 0.01) and significantly up-regulated the gene expressions of GLUT-4 and AMPK in muscle and liver tissues (P < 0.05). There was no significant difference between the control group and tiamulin group in T3, T4, GH, GU or AD (P > 0.05). Results of the present study has confirmed that octacosanol affects energy metabolism of body by regulating secretion of blood hormones and related gene expression in tissue of weaning piglets, which can reduce stress response and has an impact on performance.
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Affiliation(s)
- Lei Long
- Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agriculture Sciences, Beijing 100081, China.,Tianjin NaEr Biotechnology Co., Ltd., Tianjin 300457, China
| | - Shugeng Wu
- Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agriculture Sciences, Beijing 100081, China
| | - Jing Sun
- Tianjin NaEr Biotechnology Co., Ltd., Tianjin 300457, China
| | - Jing Wang
- Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agriculture Sciences, Beijing 100081, China
| | - Haijun Zhang
- Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agriculture Sciences, Beijing 100081, China
| | - Guanghai Qi
- Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agriculture Sciences, Beijing 100081, China
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Alves-Wagner AB, Sabino-Silva R, Campello RS, Mori RC, Machado UF. Decreased diabetes-induced glycemic impairment in WKY and SHR involves enhanced skeletal muscle Slc2a4/GLUT4 expression. Diabetol Metab Syndr 2014; 6:97. [PMID: 25228927 PMCID: PMC4164711 DOI: 10.1186/1758-5996-6-97] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 09/04/2014] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Hypertension has been associated to diabetes, and participates in the development of diabetic complications. The spontaneously hypertensive rat (SHR) is the gold standard model for the study of hypertension, and experimental diabetes has been currently investigated in SHR. Wistar-Kyoto rat is usually taken as control for SHR, however, regarding the glycemic homeostasis, WKY may be similar to SHR, when compared to the standard Wistar rat, importantly affecting the interpretation of data. Slc2a4 gene, which encodes the GLUT4 protein, is expressed in insulin-sensitive tissues, such as muscle cells and adipocytes, and alteration in Slc2a4/GLUT4 expression is inversely related to glycemic levels. We investigated the effect of diabetes on the expression of Slc2a4/GLUT4 and glycemic control in Wistar-Kyoto and SHR. FINDINGS Slc2a4 mRNA (Northern-blotting) and GLUT4 protein (Western-blotting) were investigated in skeletal muscles (soleus and extensor digitorum longus) of Wistar, Wistar-Kyoto and SHR, rendered or not diabetic for 1 month. Non-diabetic SHR shows hyperinsulinemia, and unaltered GLUT4 expression. The hyperglycemia was significantly attenuated in diabetic Wistar-Kyoto and SHR, compared to that observed in diabetic Wistar, although all of them presented the same hypoinsulinemic levels. Besides, diabetes significantly reduced Slc2a4/GLUT4 in Wistar, as expected; however, that was not observed in diabetic Wistar-Kyoto and SHR. CONCLUSIONS Non-diabetic SHR is insulin resistant, despite unaltered GLUT4 expression. Diabetic Wistar-Kyoto and diabetic SHR presented high Slc2a4/GLUT4 expression in skeletal muscle, as compared to diabetic Wistar. This Slc2a4/GLUT4 regulation does not depend on insulin level and possibly protects the WKY and SHR from severe glycemic impairment.
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Affiliation(s)
- Ana Barbara Alves-Wagner
- />Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP Brazil
| | - Robinson Sabino-Silva
- />Institute of Biomedical Sciences (ICBIM), Federal University of Uberlandia (UFU), Uberlandia, MG Brazil
| | - Raquel S Campello
- />Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP Brazil
| | - Rosana C Mori
- />Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP Brazil
| | - Ubiratan F Machado
- />Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP Brazil
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Nakahara K, Bannai M, Maruyama K, Suzuki Y, Okame R, Murakami N. Characterization of a novel genetically obese mouse model demonstrating early onset hyperphagia and hyperleptinemia. Am J Physiol Endocrinol Metab 2013; 305:E451-63. [PMID: 23736543 DOI: 10.1152/ajpendo.00540.2012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Obesity is a critical risk factor for the development of metabolic syndrome, and many obese animal models are used to investigate the mechanisms responsible for the appearance of symptoms. To establish a new obese mouse model, we screened ∼13,000 ICR mice and discovered a mouse demonstrating spontaneous obesity. We named this mouse "Daruma" after a traditional Japanese ornament. Following the fixation of the genotype, these animals exhibited obese phenotypes according to Mendel's law of inheritance. In the Daruma mouse, the leptin receptor gene sequence carried two base mutations that are good candidates for the variation(s) responsible for the obese phenotype. The Daruma mice developed characteristic visceral fat accumulation at 4 wk of age, and the white adipose and liver tissues exhibited increases in cell size and lipid droplets, respectively. No histological abnormalities were observed in other tissues of the Daruma mice, even after the mice reached 25 wk of age. Moreover, the onset of impaired leptin signaling was early and manifested as hyperleptinemia and hyperinsulinemia. Pair feeding completely inhibited obesity, although these mice rapidly developed hyperphagia and obesity followed by hyperleptinemia when pair feeding ceased and free-access feeding was permitted. Therefore, the Daruma mice exhibited unique characteristics and may be a good model for studying human metabolic syndrome.
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Affiliation(s)
- Keiko Nakahara
- Department of Veterinary Physiology, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
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Giannocco G, Oliveira KC, Crajoinas RO, Venturini G, Salles TA, Fonseca-Alaniz MH, Maciel RMB, Girardi ACC. Dipeptidyl peptidase IV inhibition upregulates GLUT4 translocation and expression in heart and skeletal muscle of spontaneously hypertensive rats. Eur J Pharmacol 2012; 698:74-86. [PMID: 23051671 DOI: 10.1016/j.ejphar.2012.09.043] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 09/19/2012] [Accepted: 09/21/2012] [Indexed: 12/22/2022]
Abstract
The purpose of the current study was to test the hypothesis that the dipeptidyl peptidase IV (DPPIV) inhibitor sitagliptin, which exerts anti-hyperglycemic and anti-hypertensive effects, upregulates GLUT4 translocation, protein levels, and/or mRNA expression in heart and skeletal muscle of spontaneously hypertensive rats (SHRs). Ten days of treatment with sitagliptin (40 mg/kg twice daily) decreased plasma DPPIV activity in both young (Y, 5-week-old) and adult (A, 20-week-old) SHRs to similar extents (~85%). However, DPPIV inhibition only lowered blood pressure in Y-SHRs (119 ± 3 vs. 136 ± 4 mmHg). GLUT4 translocation, total protein levels and mRNA expression were decreased in the heart, soleus and gastrocnemius muscle of SHRs compared to age-matched Wistar Kyoto (WKY) normotensive rats. These differences were much more pronounced between A-SHRs and A-WKY rats than between Y-SHRs and Y-WKY rats. In Y-SHRs, sitagliptin normalized GLUT4 expression in the heart, soleus and gastrocnemius. In A-SHRs, sitagliptin increased GLUT4 expression to levels that were even higher than those of A-WKY rats. Sitagliptin enhanced the circulating levels of the DPPIV substrate glucagon-like peptide-1 (GLP-1) in SHRs. In addition, stimulation of the GLP-1 receptor in cardiomyocytes isolated from SHRs increased the protein level of GLUT4 by 154 ± 13%. Collectively, these results indicate that DPPIV inhibition upregulates GLUT4 in heart and skeletal muscle of SHRs. The underlying mechanism of sitagliptin-induced upregulation of GLUT4 in SHRs may be, at least partially, attributed to GLP-1.
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Affiliation(s)
- Gisele Giannocco
- Department of Morphology and Physiology, Faculdade de Medicina do ABC, Santo André, São Paulo, SP, Brazil
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Leguisamo NM, Lehnen AM, Machado UF, Okamoto MM, Markoski MM, Pinto GH, Schaan BD. GLUT4 content decreases along with insulin resistance and high levels of inflammatory markers in rats with metabolic syndrome. Cardiovasc Diabetol 2012; 11:100. [PMID: 22897936 PMCID: PMC3439702 DOI: 10.1186/1475-2840-11-100] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/11/2012] [Indexed: 02/07/2023] Open
Abstract
Background Metabolic syndrome is characterized by insulin resistance, which is closely related to GLUT4 content in insulin-sensitive tissues. Thus, we evaluated the GLUT4 expression, insulin resistance and inflammation, characteristics of the metabolic syndrome, in an experimental model. Methods Spontaneously hypertensive neonate rats (18/group) were treated with monosodium glutamate (MetS) during 9 days, and compared with Wistar-Kyoto (C) and saline-treated SHR (H). Blood pressure (BP) and lipid levels, C-reactive protein (CRP), interleukin 6 (IL-6), TNF-α and adiponectin were evaluated. GLUT4 protein was analysed in the heart, white adipose tissue and gastrocnemius. Studies were performed at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age. Results MetS rats were more insulin resistant (p<0.001, all ages) and had higher BP (3-mo: p<0.001, 6-mo: p = 0.001, 9-mo: p = 0.015) as compared to C. At 6 months, CRP, IL-6 and TNF-α were higher (p<0.001, all comparisons) in MetS rats vs H, but adiponectin was lower in MetS at 9 months (MetS: 32 ± 2, H: 42 ± 2, C: 45 ± 2 pg/mL; p<0.001). GLUT4 protein was reduced in MetS as compared to C rats at 3, 6 and 9-mo, respectively (Heart: 54%, 50% and 57%; Gastrocnemius: 37%, 56% and 50%; Adipose tissue: 69%, 61% and 69%). Conclusions MSG-treated SHR presented all metabolic syndrome characteristics, as well as reduced GLUT4 content, which must play a key role in the impaired glycemic homeostasis of the metabolic syndrome.
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Affiliation(s)
- Natalia M Leguisamo
- Laboratório de Experimentação Animal e Laboratório de Cardiologia Molecular e Celular, Instituto de Cardiologia/Fundação, Universitária de Cardiologia, Bairro Santana, Porto Alegre, RS, Brazil
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Abstract
Insulin resistance and hyperinsulinemia are common findings in patients with essential hypertension. Recent evidence indicates that these impairments in glucose metabolism may play a role not only in the development of type 2 diabetes, but also in the onset and persistence of hypertension, dyslipidemia, and abdominal obesity. The accumulation of these risk factors constitutes a high-risk group of cardiovascular diseases, the so-called metabolic syndrome. Insulin resistance has also been reported in several animal models for hypertension, including the spontaneously hypertensive rat (SHR) and the fructose-fed rat (FFR). SHRs and FFRs have been employed in many studies to investigate the mechanisms and pathophysiology of insulin resistance and hypertension, but the precise mechanism of insulin resistance remains to be clarified. In this review, the possible mechanisms of insulin resistance in SHRs and FFRs are summarized.
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Affiliation(s)
- Kazuaki Shimamoto
- The Second Department of Internal Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
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Cesaretti MLR, Kohlmann Junior O. Modelos experimentais de resistência à insulina e obesidade: lições aprendidas. ACTA ACUST UNITED AC 2006; 50:190-7. [PMID: 16767285 DOI: 10.1590/s0004-27302006000200005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Para melhor compreender o papel de cada um dos elementos envolvidos na fisiopatologia da obesidade e da resistência à insulina, pesquisadores utilizam-se de modelos experimentais, que podem determinar de maneira controlada o papel de cada um dos componentes da resistência à insulina e obesidade e, desta maneira, fornecer subsídios para a melhor compreensão da fisiopatolologia e tratamento da resistência à insulina e obesidade. A obesidade e a resistência à insulina experimentais podem ser verificadas quando ocorre diminuição da resposta à leptina, seja por menor produção ou alteração no seu receptor, modificações no receptor de insulina, por deleção do receptor ou alteração da transdução dos seu sinal, exacerbação do efeito de peptídeos orexígenos e/ou menor ação de peptídeos anorexígenos no hipotálamo, ou ainda secundária à hipertensão arterial, como nos ratos espontaneamente hipertensos. O excesso de glicocorticóides, a adição de uma dieta rica em frutose, ou ainda uma dieta hipercalórica, além da lesão hipotalâmica induzida pela administração neonatal de monoglutamato de sódio, são exemplos de obesidade e resistência à insulina induzidos.
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Abstract
A regulação da homeostasia intra e extra-celular da glicose está diretamente relacionada ao controle preciso da expressão dos genes que codificam as diferentes isoformas de proteínas transportadoras de glicose, as quais se expressam de maneira tecido-específica, em conseqüência do padrão de ativação dos fatores transcricionais reguladores de cada gene, em cada tipo celular. A síndrome metabólica (SM) abrange uma grande variedade de alterações fisiopatológicas, todas de repercussões sistêmicas, acometendo os mais distintos territórios do organismo, nos quais alterações nos transportadores de glicose presentes são observadas em maior ou menor grau. A presente revisão abordará as alterações na expressão de transportadores de glicose claramente demonstradas na literatura, cujas repercussões nos fluxos territoriais de glicose auxiliam na compreensão de mecanismos fisiopatológicos da SM, assim como dos tratamentos propostos para esta entidade.
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Affiliation(s)
- Ubiratan Fabres Machado
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP.
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Guan H, Arany E, van Beek JP, Chamson-Reig A, Thyssen S, Hill DJ, Yang K. Adipose tissue gene expression profiling reveals distinct molecular pathways that define visceral adiposity in offspring of maternal protein-restricted rats. Am J Physiol Endocrinol Metab 2005; 288:E663-73. [PMID: 15562247 DOI: 10.1152/ajpendo.00461.2004] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
There is increasing evidence that poor early growth confers an increased risk of type 2 diabetes, hypertension, and other features of the metabolic syndrome in later life. We hypothesized that this may result from poor nutrition during early life exerting permanent effects on the structure and function of key metabolic organ systems. To study the long-term impact of early-life undernutrition on susceptibility to visceral adiposity, we used a rat model of maternal protein restriction (MPR) in which dams were fed a low-protein diet (containing 8% instead of 20% protein in control diet) throughout pregnancy and lactation. MPR offspring were born smaller than controls (offspring of dams on control diet) and in adulthood developed visceral adiposity. We compared the pattern of gene expression in visceral adipose tissue (VAT) between MPR offspring and controls with Affymetrix rat expression arrays. Of the total number of genes and expressed sequence tags analyzed (15,923 probe sets), 9,790 (61.5%) were expressed in VAT. We identified 650 transcripts as differentially expressed > or =1.5-fold in the VAT of MPR offspring. Gene ontology analysis revealed a global upregulation of genes involved in carbohydrate, lipid, and protein metabolism. A number of genes involved in adipocyte differentiation, angiogenesis, and extracellular matrix remodeling were also upregulated. However, in marked contrast to other rodent models of obesity, the expression of a large number of genes associated with inflammation was reduced in this rat model. Thus visceral adiposity in this early-life programmed rat model is marked by dynamic changes in the transcriptional profile of VAT. Our data provide new insights into the molecular mechanisms that underlie the early-life programming of visceral adiposity.
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Affiliation(s)
- Haiyan Guan
- Department of Obstetrics and Gynaecology, Canadian Institutes of Health Research Group in Fetal and Neonatal Health and Development, Children's Health Research Institute, University of Western Ontario, Canada
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Bustamante M, Hasler U, Kotova O, Chibalin AV, Mordasini D, Rousselot M, Vandewalle A, Martin PY, Féraille E. Insulin potentiates AVP-induced AQP2 expression in cultured renal collecting duct principal cells. Am J Physiol Renal Physiol 2004; 288:F334-44. [PMID: 15494547 DOI: 10.1152/ajprenal.00180.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In the renal collecting duct (CD), water reabsorption depends on the presence of aquaporin-2 (AQP2) in the apical membrane of principal cells. AQP2 expression and subcellular repartition are under the control of AVP. Some pieces of experimental evidence indicate that additional hormonal factors, including insulin, may also control AQP2 expression and thereby CD water permeability. We have previously shown that AVP induces endogenous AQP2 expression in cultured mouse mpkCCD(cl4) CD principal cells (23). In the present study, we investigated the effect of insulin on AQP2 expression in mpkCCD(cl4) cells. Addition of insulin to the basal medium of cells grown on filters slightly increased AQP2 mRNA and protein expression, whereas insulin potentiated the effect of AVP. The potentiation of AVP-induced AQP2 expression by insulin was abolished by actinomycin D, a transcriptional inhibitor. Analysis of AQP2 protein expression under conditions of AVP washout and/or in the presence of chloroquine, a lysosomal degradation inhibitor, revealed that insulin did not significantly alter AQP2 protein degradation. Inhibition of ERK, p38 kinase, and phosphatidylinositol 3'-kinase (PI 3-kinase) activities prevented the insulin-induced stimulation of AQP2 expression, whereas inhibition of PKC has no effect. Taken together, our results indicate that insulin increased AQP2 protein expression mostly through increased AQP2 mRNA levels in cultured mpkCCD(cl4) cells. This effect most likely relies on increased AQP2 gene transcription in response to MAPK and PI 3-kinase activation.
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Affiliation(s)
- Mauro Bustamante
- Fondation pour Recherches Médicales, Service of Nephrology, 64 Ave. de la Roseraie, CH-1211 Geneva 4, Switzerland
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