title: 17β-estradiol upregulates oxytocin and the oxytocin receptor in C2C12 myotubes.
abstract: BACKGROUND
  The endocrinology of skeletal muscle is highly complex and many issues about hormone action in skeletal muscle are still unresolved. Aim of the work is to improve our knowledge on the relationship between skeletal muscle and 17β-estradiol.
  
  
  METHODS
  The skeletal muscle cell line C2C12 was treated with 17β-estradiol, the oxytocin peptide and a combination of the two hormones. The mRNA levels of myogenic regulatory factors, myosin heavy chain, oxytocin, oxytocin receptor and adipogenic factors were analysed in C2C12 myotubes.
  
  
  RESULTS
  It was demonstrated that C2C12 myoblasts and myotubes express oxytocin and its receptor, in particular the receptor levels physiologically increase in differentiated myotubes. Myotubes treated with 17β-estradiol overexpressed oxytocin and oxytocin receptor genes by approximately 3- and 29-fold, respectively. A decrease in the expression of fatty acid binding protein 4 (0.62-fold), a fat metabolism-associated gene, was observed in oxytocin-treated myotubes. On the contrary, fatty acid binding protein 4 was upregulated (2.66-fold) after the administration of the combination of 17β-estradiol and oxytocin. 17β-estradiol regulates oxytocin and its receptor in skeletal muscle cells and they act in a synergic way on fatty acid metabolism.
  
  
  CONCLUSIONS
  Oxytocin and its receptor are physiologically regulated along differentiation. 17β-estradiol regulates oxytocin and its receptor in skeletal muscle cells. 17β-estradiol and oxytocin act in a synergic way on fatty acid metabolism. A better understanding of the regulation of skeletal muscle homeostasis by estrogens and oxytocin peptide could contribute to increase our knowledge of muscle and its metabolism.
authors.affiliation: Department of Veterinary Science, University of Turin , Grugliasco , Torino , Italy.
authors.forename: Enrica
authors.initials: E
authors.lastname: Berio
authors.affiliation: Department of Veterinary Science, University of Turin , Grugliasco , Torino , Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Divari
authors.affiliation: Department of Veterinary Science, University of Turin , Grugliasco , Torino , Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Starvaggi Cucuzza
authors.affiliation: Department of Veterinary Science, University of Turin , Grugliasco , Torino , Italy.
authors.forename: Bartolomeo
authors.initials: B
authors.lastname: Biolatti
authors.affiliation: Department of Veterinary Science, University of Turin , Grugliasco , Torino , Italy.
authors.forename: Francesca Tiziana
authors.initials: FT
authors.lastname: Cannizzo
keywords: Estrogen; Gene expression regulation; Oxytocin; Skeletal muscle cell