Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/313934
Type: TESE
Title: Tungstato de sodio reduz a resistencia a insulina induzida por dexametasona em ratos
Author: Nunes, Wilton Marlindo Santana
Advisor: Boschiero, Antonio Carlos, 1943-
Abstract: Resumo: Dentre os vários compostos inorgânicos que mimetizam as ações da insulina os derivados do vanadato são, sem dúvida, os mais estudados. No presente trabalho, analisamos os efeitos de um desses derivados, o tungstato de sódio, sobre a homeostasia da glicose e a secreção de insulina em ilhotas de Langerhans isoladas de ratos tornados resistentes à insulina pela dexametasona. Quinze dias antes dos experimentos, ratos machos adultos da linhagem Wistar foram distribuídos casualmente em quatro grupos, a saber: controle, dexametasona, tungstato e dexametasona + tungstato. Durante os quinze dias, os ratos dos grupos controle e dexametasona tiveram livre acesso à água e ração. Os ratos dos grupos tungstato e dexametasona + tungstato receberam tungstato de sódio (2mg/ml), dissolvido na água de beber. Nos últimos 5 dias que precederam os experimentos, os ratos dos grupos dexametasona e dexametasona + tungstato receberam, via intraperitoneal, doses diárias de dexametasona (1 mg/kg-

Abstract: Among the severa I inorganic compounds that mimic the effect of insulin vanadium derivatives are the most widely studied. In the present work we have analyzed the effects of tungstate on glucose homeostasis and insulin secretion in healthy and in insulin resistant rats by dexamethasone. Fifteen days before the experiments the rats were randomly distributed in four groups: control, dexamethasone, tungstate and dexamethasone + tungstate. Control and dexamethasone groups had free access to water. Tungstate and dexamethasone + tungstate groups received tungstate dissolved in the drink water (2mg/ml). The dexamethasone and dexamethasone + tungstate groups received during the last 5 days daily doses of 1 mg/Kg-1 of dexamethasone, intraperitoneally. In insulin resistant rats, tungstate treatment normalized plasma glucose whereas plasma insulin and triglycerides remained significantly higher than controls. The glucose disappearance rate after an ivlTT and the glucose uptake by soleus muscle of insulin resistant rats were lower compared to control rats and was normalized by tungstate. The dose-response curve of insulin secretion (5.6 to 27.7 mM glucose) in isolated islets from dexamethasone-treated rats was shifted to the left compared to control islets. Administration of tungstate to these animais induced a dose-response curve closar to contrai islets. The EC50 for the dose-response curves were 13.7, 7.9, 15.7 and 11.8 mM glucose for contrai, ...J dexamethasone, tungstate and dexamethasone + tungstate-treated rats, respectively. In conclusion, tungstate-induced plasma glucose normalization seems to be, at least in part, dependent on the restoration of glucose uptake by muscle cells of insulin resistant rats
Subject: Glicose
Insulina
Language: Português
Editor: [s.n.]
Date Issue: 2001
Appears in Collections:IB - Tese e Dissertação

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