title: Effects of Growth Hormone on Cardiac Remodeling During Resistance Training in Rats.
abstract: BACKGROUND
  Although the beneficial effects of resistance training (RT) on the cardiovascular system are well established, few studies have investigated the effects of the chronic growth hormone (GH) administration on cardiac remodeling during an RT program.
  
  
  OBJECTIVE
  To evaluate the effects of GH on the morphological features of cardiac remodeling and Ca2+ transport gene expression in rats submitted to RT.
  
  
  METHODS
  Male Wistar rats were divided into 4 groups (n = 7 per group): control (CT), GH, RT and RT with GH (RTGH). The dose of GH was 0.2 IU/kg every other day for 30 days. The RT model used was the vertical jump in water (4 sets of 10 jumps, 3 bouts/wk) for 30 consecutive days. After the experimental period, the following variables were analyzed: final body weight (FBW), left ventricular weight (LVW), LVW/FBW ratio, cardiomyocyte cross-sectional area (CSA), collagen fraction, creatine kinase muscle-brain fraction (CK-MB) and gene expressions of SERCA2a, phospholamban (PLB) and ryanodine (RyR).
  
  
  RESULTS
  There was no significant (p > 0.05) difference among groups for FBW, LVW, LVW/FBW ratio, cardiomyocyte CSA, and SERCA2a, PLB and RyR gene expressions. The RT group showed a significant (p < 0.05) increase in collagen fraction compared to the other groups. Additionally, the trained groups (RT and RTGH) had greater CK-MB levels compared to the untrained groups (CT and GH).
  
  
  CONCLUSIONS
  GH may attenuate the negative effects of RT on cardiac remodeling by counteracting the increased collagen synthesis, without affecting the gene expression that regulates cardiac Ca2+ transport.
authors.affiliation: Universidade do Oeste Paulista, Presidente Prudente, SP, Brazil.
authors.forename: Adriana
authors.initials: A
authors.lastname: Junqueira
authors.affiliation: Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Antônio Carlos
authors.initials: AC
authors.lastname: Cicogna
authors.affiliation: Universidade do Oeste Paulista, Presidente Prudente, SP, Brazil.
authors.forename: Letícia Estevam
authors.initials: LE
authors.lastname: Engel
authors.affiliation: Universidade do Oeste Paulista, Presidente Prudente, SP, Brazil.
authors.forename: Maiara Almeida
authors.initials: MA
authors.lastname: Aldá
authors.affiliation: Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Loreta Casquel
authors.initials: LC
authors.lastname: de Tomasi
authors.affiliation: Universidade do Oeste Paulista, Presidente Prudente, SP, Brazil.
authors.forename: Rogério
authors.initials: R
authors.lastname: Giuffrida
authors.affiliation: Universidade do Oeste Paulista, Presidente Prudente, SP, Brazil.
authors.forename: Inês Cristina
authors.initials: IC
authors.lastname: Giometti
authors.affiliation: Universidade do Oeste Paulista, Presidente Prudente, SP, Brazil.
authors.forename: Ana Paula Coelho Figueira
authors.initials: AP
authors.lastname: Freire
authors.affiliation: Universidade do Norte do Paraná, Londrina, PR, Brazil.
authors.forename: Andreo Fernando
authors.initials: AF
authors.lastname: Aguiar
authors.affiliation: Universidade do Oeste Paulista, Presidente Prudente, SP, Brazil.
authors.forename: Francis Lopes
authors.initials: FL
authors.lastname: Pacagnelli
mesh_terms: D000818:Animals; D001835:Body Weight; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000032:analysis; D003094:Collagen / Q000032:analysis / Q000187:drug effects; D052276:Creatine Kinase, BB Form / Q000097:blood / Q000187:drug effects; D015870:Gene Expression; D013006:Growth Hormone / Q000494:pharmacology*; D006352:Heart Ventricles / Q000187:drug effects; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects; D009929:Organ Size; D016133:Polymerase Chain Reaction; D017208:Rats, Wistar; D055070:Resistance Training / Q000379:methods*; D012433:Ryanodine / Q000032:analysis; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000032:analysis / Q000187:drug effects; D013997:Time Factors; D020257:Ventricular Remodeling / Q000187:drug effects* / Q000235:genetics; D000099211:Phospholamban
chemical_list: D002118:Calcium; D002135:Calcium-Binding Proteins; D003094:Collagen; D052276:Creatine Kinase, BB Form; D013006:Growth Hormone; D012433:Ryanodine; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000099211:Phospholamban; C506948:Atp2a2 protein, rat