title: Obesity does not lead to imbalance between myocardial phospholamban phosphorylation and dephosphorylation.
abstract: BACKGROUND
  The activation of the beta-adrenergic system promotes G protein stimulation that, via cyclic adenosine monophosphate (cAMP), alters the structure of protein kinase A (PKA) and leads to phospholamban (PLB) phosphorylation. This protein participates in the system that controls intracellular calcium in muscle cells, and it is the primary regulator of sarcoplasmic reticulum calcium pump activity. In obesity, the beta-adrenergic system is activated by the influence of increased leptin, therefore, resulting in higher myocardial phospholamban phosphorylation via cAMP-PKA.
  
  
  OBJECTIVE
  To investigate the involvement of proteins which regulate the degree of PLB phosphorylation due to beta-adrenergic activation in obesity. In the present study, we hypothesized that there is an imbalance between phospholamban phosphorylation and dephosphorylation, with prevalence of protein phosphorylation.
  
  
  METHODS
  Male Wistar rats were randomly distributed into two groups: control (n = 14), fed with normocaloric diet; and obese (n = 13), fed with a cycle of four unsaturated high-fat diets. Obesity was determined by the adiposity index, and protein expressions of phosphatase 1 (PP-1), PKA, PLB, phosphorylated phospholamban at serine16 (PPLB-Ser16) were assessed by Western blot.
  
  
  RESULTS
  Obesity caused glucose intolerance, hyperinsulinemia, hypertriglyceridemia, hyperleptinemia and did not alter the protein expression of PKA, PP-1, PLB, PPLB-Ser16.
  
  
  CONCLUSIONS
  Obesity does not promote an imbalance between myocardial PLB phosphorylation and dephosphorylation via beta-adrenergic system.
authors.affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Paula Paccielli
authors.initials: PP
authors.lastname: Freire
authors.affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Carlos Augusto Barnabe
authors.initials: CA
authors.lastname: Alves
authors.affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Adriana Fernandes de
authors.initials: AF
authors.lastname: Deus
authors.affiliation: Centro de Educação Física e Desportos, Universidade Federal do Espírito Santo, Vitória, ES, Brazil.
authors.forename: Ana Paula Lima
authors.initials: AP
authors.lastname: Leopoldo
authors.affiliation: Centro de Educação Física e Desportos, Universidade Federal do Espírito Santo, Vitória, ES, Brazil.
authors.forename: André Soares
authors.initials: AS
authors.lastname: Leopoldo
authors.affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Danielle Cristina Tomaz da
authors.initials: DC
authors.lastname: Silva
authors.affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Loreta Casquel de
authors.initials: LC
authors.lastname: Tomasi
authors.affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Dijon Henrique Salomé
authors.initials: DH
authors.lastname: Campos
authors.affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Antonio Carlos
authors.initials: AC
authors.lastname: Cicogna
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002784:Cholesterol / Q000097:blood; D059305:Diet, High-Fat; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005951:Glucose Tolerance Test; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D008075:Lipoproteins, HDL / Q000097:blood; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism*; D010766:Phosphorylation; D011897:Random Allocation; D017208:Rats, Wistar; D014280:Triglycerides / Q000097:blood; D020257:Ventricular Remodeling / Q000502:physiology; D000099211:Phospholamban
chemical_list: D001786:Blood Glucose; D002135:Calcium-Binding Proteins; D002784:Cholesterol; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D020738:Leptin; D008075:Lipoproteins, HDL; D014280:Triglycerides; D000099211:Phospholamban