|Support type:||Scholarships in Brazil - Master|
|Effective date (Start):||April 01, 2010|
|Effective date (End):||March 31, 2012|
|Field of knowledge:||Biological Sciences - Physiology - Physiology of Organs and Systems|
|Principal Investigator:||Vagner Roberto Antunes|
|Grantee:||Izabela Martina Ramos Ribeiro de Toledo|
|Home Institution:||Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil|
The capacity of the human body to preserve energy reserves in situations of food abundance with the aim of generating surplus stores critical for vital organ function, during periods of famine, is of extreme importance. Insulin is one of the major hormones responsible for this function. In post-absorption, insulin promotes the uptake of glucose by peripheral tissues, especially by those expressing GLUT4. Generally, hepatic glucose production (HGP) is determined by the rate of glycogenesis and glycogenolysis. Insulin exerts a potent hepatic action resulting in suppression of HGP. Sympathetic activation increases HGP by stimulating both glycogenolysis and glycogenesis. Stimulation of glycogenesis is driven by the increase of circulating catecholamines secreted by the adrenal medulla and post-ganglionic release of catecholamines by sympathetic fibers that innervate the liver while parasympathetic activation results in decreased HGP. Despite metabolic modulation of the direct glycogenesis by insulin being relatively well defined, little is known about the indirect regulation of HGP mediated by insulin's actions in territories outside the liver and the transmission of information from the central nervous system to the liver. Moreover, it is not yet well known how the sympathetic and vagal autonomic balance operates as a consequence of the central actions of insulin. Thus, the purpose of this study is to investigate the effects of insulin injected into the central nervous system, on HGP, the expression of PEPCK and G-6-pase in this organ and evaluate if these changes are dependent on sympathetic hyperactivity in hypertensive animals.