Efeitos da administração de metformina e pioglitazona sobre o metabolismo glicídico e a pressão arterial de ratos hipertensos tornados obesos pela injeção neonatal de glutamato monossódico

• Ano de defesa: 2009
• Autor(a) principal: Ferreira, Carolina Baeta Neves Duarte [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Pressão arterial; Ratos endogâmicos SHR; Metformina
• Link de acesso: http://repositorio.unifesp.br/handle/11600/9390

Background: Insulin resistance and visceral adiposity are key factors regarding metabolic syndrome (MS) physiopathology. Insulin resistance pharmacologic treatment might control diverse factors including glicemic abnormalities and blood pressure. Objectives: To produce MS model through monossodium glutamate (MSG) administration to spontaneously hypertensive rats (SHR) and analyze metformin and pioglitazone effects upon tail pressure, weight, glucose metabolism, epididimal fat (EF) and left ventricular mass weight. Methods: SHR received MSG until 11th day after born (SHR-MSG). Controls received saline (SHR). After 12 weeks, part of the two groups received metformin (SHRMeformin and SHR-MSG-Metformin) or pioglitazone (SHR-Pioglitazone and SHRMSG- Pioglitazone) during 12 weeks. Tail pressure and weight were recorded. After, oral glucose tolerance test (OGTT) was performed and areas under glucose (AUCG) and insulin (AUCI) curves and insulin sensibility index were measured. Following OGTT, EF and ventricular mass were assessed. Results: MSG administration increased insulin resistance and EF deposition without affecting tail pressure. Metformin improved insulin sensibility, reduced epididimal fat content and tail pressure. Pioglitazone didn´t impact upon tail pressure in both groups; increased weight in SHR-MSG; worsened insulin sensitivity in SHR, but decreased visceral fat content in SHR-MSG. Conclusions: MSG induced visceral obesity and worsened glucose metabolism in SHR, without affecting tail pressure. Metformin improved glucose metabolism and reduced tail pressure. Both reduce visceral fat deposition. These data points to hepatic insulin resistance as a key factor in metabolic disturbances and reveal benefical cardiovascular effects. Pioglitazone failure might be explained in SHR and SHR-MSG due to CD36 mutation previously described in this rat strain.