title: Effects of tail suspension on serum testosterone and molecular targets regulating muscle mass.
abstract: BACKGROUND
  The contribution of reduced testosterone levels to tail suspension (TS)-induced muscle atrophy remains equivocal. The molecular mechanism by which testosterone regulates muscle mass during TS has not been investigated.
  
  
  METHODS
  Effects of TS on serum testosterone levels, muscle mass, and expression of muscle atrophy- and hypertrophy-inducing targets were measured in soleus (SOL) and extensor digitorum longus (EDL) muscles after testosterone administration during 1, 5, and 14 days of TS in male mice.
  
  
  RESULTS
  TS produced an increase followed by a transient drop in testosterone levels. Muscle atrophy was associated with downregulation of Igf1 and upregulation of Mstn, Redd1, Atrogin-1, and MuRF1 mRNA with clear differences in Igf1, Mstn, and MAFbx/Atrogin-1 gene expression between SOL and EDL. Testosterone supplementation did not affect muscle mass or protein expression levels during TS. Conclusions The known anabolic effects of testosterone are not sufficient to ameliorate loss of muscle mass during TS.
authors.affiliation: Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium.
authors.forename: Hélène
authors.initials: H
authors.lastname: De Naeyer
authors.affiliation: Centre for Physical Activity and Nutrition Research, Deakin University, Melbourne, Victoria, Australia.
authors.forename: Séverine
authors.initials: S
authors.lastname: Lamon
authors.affiliation: Centre for Physical Activity and Nutrition Research, Deakin University, Melbourne, Victoria, Australia.
authors.forename: Aaron P
authors.initials: AP
authors.lastname: Russell
authors.affiliation: Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium.
authors.forename: Inge
authors.initials: I
authors.lastname: Everaert
authors.affiliation: Department of Endocrinology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Annelies
authors.initials: A
authors.lastname: De Spaey
authors.affiliation: Institute of Neuroscience, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Cécile
authors.initials: C
authors.lastname: Jamart
authors.affiliation: Department of Basic Medical Sciences, Division of Physiology, Ghent University, Ghent, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: Vanheel
authors.affiliation: Department of Endocrinology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Youri
authors.initials: Y
authors.lastname: Taes
authors.affiliation: Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Derave
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D005786:Gene Expression Regulation; D019417:Hindlimb Suspension / Q000009:adverse effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009133:Muscular Atrophy / Q000097:blood* / Q000473:pathology; D012313:RNA / Q000097:blood; D011897:Random Allocation; D013739:Testosterone / Q000097:blood*
chemical_list: D015415:Biomarkers; D013739:Testosterone; D012313:RNA
keywords: AKT; Atrogin-1; disuse atrophy; tail suspension; testosterone