title: Acute growth hormone administration increases myoglobin expression and Glut4 translocation in rat cardiac muscle cells.
abstract: OBJECTIVE
  Oxygen (O2) and glucose are important energy sources for the heart. This study sought to investigate the effects of acute growth hormone (GH) administration on the expression of myoglobin (Mb) and Glut4 glucose transporter, two important limiting factors for O2 and glucose utilization for energy production, in cardiac muscle cells of treated rats.
  
  
  METHODS
  Male Wistar rats were sacrificed at 30, 45, 90 and 120 min after a single dose of intraperitoneal (ip) rat GH (1.5 mg/kg) or vehicle administration, and total RNA and protein (from whole cell or subcellular fractions) were extracted from cardiomyocytes (left ventricles) of these animals.
  
  
  RESULTS
  Acute GH injection led to a significant increase in both Mb mRNA and protein levels, and stimulated Glut4 protein translocation to the plasma membrane of cardiac cells.
  
  
  CONCLUSIONS
  These results suggest that GH exerts some of its effects on cardiomyocytes shortly after the first administration inducing the expression of proteins potentially involved in cardiac performance.
authors.affiliation: Laboratório de Fisiologia do Tecido Adiposo, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil. Electronic address: rsertie@yahoo.com.br.
authors.forename: Rogério Antônio Laurato
authors.initials: RA
authors.lastname: Sertié
authors.affiliation: Centro de Pesquisa Experimental, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
authors.forename: Andréa Laurato
authors.initials: AL
authors.lastname: Sertié
authors.affiliation: Faculdade de Medicina do ABC, Santo André, SP, Brazil.
authors.forename: Gisele
authors.initials: G
authors.lastname: Giannocco
authors.affiliation: Laboratório de Regulação Hormonal e Expressão Gênica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Leonice Lourenço
authors.initials: LL
authors.lastname: Poyares
authors.affiliation: Laboratório de Regulação Hormonal e Expressão Gênica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Maria Tereza
authors.initials: MT
authors.lastname: Nunes
mesh_terms: D000818:Animals; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism*; D013006:Growth Hormone / Q000494:pharmacology*; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D009211:Myoglobin / Q000096:biosynthesis*; D010101:Oxygen Consumption / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D051275:Glucose Transporter Type 4; D009211:Myoglobin; D011994:Recombinant Proteins; C495694:Slc2a4 protein, rat; D013006:Growth Hormone; D005947:Glucose
keywords: Acute growth hormone; Cardiovascular function; Glucose transporter Glut4; Myoglobin