Miranda 2013 Thesis Instituto de Biologia - Rio de Janeiro

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Miranda GL (2013) Sinalização da grelina no coração de camundongos obesos após hipernutrição durante a lactação / Ghrelin signaling in the heart of obese mice after overnutrition during lactation. Thesis Instituto de Biologia - Rio de Janeiro 93pp.

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Miranda GL (2013) Thesis Instituto de Biologia - Rio de Janeiro

Abstract: Ghrelin, an endogenous ligand of the growth hormone secretagogue receptor (GHS-R), has been suggested to be associated to obesity, insulin secretion, cardiovascular growth and homeostasis. GHS-R has been found in most of the tissues, and among the hormone action it is included the regulation of heart energy metabolism. Therefore, hypernutrition during early life leads to obesity, induces cardiac hypertrophy, compromises myocardial function, inducing heart failure in adulthood. We examined ghrelin signaling process in cardiac remodeling in these obese adult mice. We examined key proteins of cardiomyocyte metabolism in heart left ventricle from overfed (OG) and control (CG) groups from adult mice (180 days) overfed during lactation. Obesity was induced by litter reduction. Therefore, the study was done in adult mice 180 days old (OG, obese group (n=10) and CG, control group (n=10). The cardiomyocytes (cmy) of left ventricle were analyzed by light microscopy and stereology. The content and phosphorylation of cardiac proteins: growth hormone secretagogue receptor 1a (GHSR-1a), protein kinase B (AKT and pAKT), phosphatidil inositol 3 kinase (PI3K), AMP-activated protein kinase (AMPK and pAMPK), mTOR and pmTOR, BAX, Bcl2 and actin was achieved by western blotting. GHSR-1a gene expression was analyzed to RT-PCR. We performed high-resolution respirometry of cardiomyocytes with OROBOROS® Oxygraph-2k. Statistical significance was determined by Student t-test for unpaired. P< 0.05 was considered statistical significant. Body weight, blood glucose, liver weight, and visceral fat weight were higher in OG than CG group. Obese mice had increased heart weight and heart weight/TL (tibia length) indicating cardiac remodeling and hypertrophy, increased GHSR-1a content and expression in the heart, associated to PI3K content, increased AKT content and phosphorylation (P< 0.05), decreased Bcl2 content. In contrast, AMPK and mTOR content and phosphorylation in heart were not...(AU)

Labels: MiParea: Respiration, mt-Medicine  Pathology: Obesity 

Organism: Mouse 

HRR: Oxygraph-2k