Chronic stress action on metabolic effects and glycogen content and GLUT4 expression in rat heart

• Grant number: 14/14744-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2014
• End date: December 31, 2015
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Fernanda Klein Marcondes
• Grantee: Maeline Santos Morais Carvalho
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil
• Associated research grant: 10/51904-9 - Renin angiotensin and kallikrein kinin systems in hypertension, obesity, diabetes, desnutrition and sepsis: molecular, cellular and physiopathologic mechanisms, AP.TEM

Abstract

Chronic stress is a risk factor for cardiometabolic diseases such as hyperglycemia, insulin resistance, dyslipidemia and diabetes. In diabetes, there are changes in the utilization of energetic fuels in all tissues due to insulin deficiency. This reduces the utilization of glucose and modifies the activity of glucose transporters 4 (GLUT4 ) in cardiac and skeletal muscles, increasing the blood levels of fatty acids and cardiac intracellular glycogen. The increased release of fatty acids from adipocytes and liver results in elevated circulating fatty acids and triglycerides, which is the biggest factor involved in high oxidation and fatty acid uptake in cardiomyocytes. In situations where the availability of fatty acids exceeds the cellular oxidative capacity, accumulation of intracellular triglycerides, associated with cardiac lipotoxicity may occur. Although these mechanisms are well established in situations of chronic hyperglycemia, diabetes and / or treatment with glucocorticoids it is not yet established whether these changes also occur in cardiac tissue of chronically stressed animals. Under stress sustained high levels of glucocorticoids impair insulin action and activity of GLUT 4 in cardiac myocytes, stimulating gluconeogenesis, lipolytic metabolism and free fatty acids release. Thus, the aim of this study is to evaluate the effect of moderate and chronic unpredictable stress on the glycogen content and the expression of GLUT4 in the rat heart. (AU)