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Master's Dissertation
DOI
10.11606/D.42.2008.tde-03062008-151016
Document
Author
Full name
João Paulo Gabriel Camporez
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2008
Supervisor
Committee
Carvalho, Carla Roberta de Oliveira (President)
Carpinelli, Angelo Rafael
Hirata, Aparecida Emiko
Title in Portuguese
Efeito in vitro do deidroepiandrosterona (DHEA) sobre a via IRS/PI3-K/Akt e secreção de insulina em ilhotas pancreáticas de ratos.
Keywords in Portuguese
Diabetes Mellitus
Expressão gênica
Homônios sexuais
Ilhotas de Langerhans
Receptores da insulina
Sinalização da insulina
Abstract in Portuguese
A administração de deidroepiandrosterona (DHEA) tem resultado em efeitos anti-diabetogênicos em animais de experimentação e no homem. Assim, o objetivo desse trabalho é avaliar o efeito do DHEA in vitro na expressão protéica do IR, do IRS-1, IRS-2, PI3-K, Akt, ERK-1/2; na expressão gênica do PDX-1, do PGC-1, da insulina, do GLUT-2 e da glicocinase; e avaliar a secreção estática de insulina de ilhotas pancreáticas de ratos. O cultivo das ilhotas por 24 horas com DHEA, não induziu nenhuma alteração tanto na expressão das proteínas quanto na secreção estática de insulina estimulada por glicose. Ocorreu aumento da fosforilação de ERK-1/2 e na expressão gênica do PGC-1. As células RINm5F, cultivadas por 72 horas com DHEA, apresentaram aumento da expressão total de IRS-1 e IRS-2. Concluímos, que 24 horas de cultura com ilhotas não é tempo suficiente para observar nenhuma alteração induzida pelo DHEA, na secreção de insulina, e na expressão das proteínas da via IRS/PI3-K/Akt. Células RINm5F podem ser um modelo alternativo para investigar os efeitos diretos do DHEA.
Title in English
Effect in vitro of dehydroepiandrosterone (DHEA) on IRS/PI3-K/Akt pathway and insulin secretion on rats pancreatic islets.
Keywords in English
Diabetes Mellitus
Gene expression
Insulin receptor
Insulin signaling
Langerhans islets
Sexual hormone
Abstract in English
The dehydroepiandrosterone (DHEA) administration has resulted in reduction of abdominal fat and protection against insulin resistance from experimental animals and humans. So, the purpose of this project is measure the in vitro effects from DHEA: on protein expression of insulin receptor, the proteins IRS-1, IRS-2, PI3-K, Akt, and ERK-1/2; on gene expression of transcriptional factors PDX-1 and PGC-1, insulin, glucose transport GLUT-2 and glicocinase; and to measure the static insulin secretion, on cultured pancreatic islets of the rat. The culture of pancreatic islet for 24 hours with DHEA, did not induce nothing alteration on protein expression of the IR, IRS-1, IRS-2, PI3-K, Akt-1 and ERK-1/2, and static insulin secretion induced by glucose. However, happened increase ERK-1/2 phosphorylation and PGC-1 gene expression. The RINm5F cells, cultured by 72 hours, showed increase of the IRS-1 and IRS-2 expression. We conclude that 24 hours of the pancreatic islets culture are not sufficient time to look any alteration induced by DHEA, on insulin secretion, and on protein expression involved on IRS/PI3-K/Akt pathway. RINm5F cells can be an alternative model to research the direct effects from DHEA.
 
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Publishing Date
2008-06-11
 
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