title: Leptin and ghrelin levels in humans during physical inactivity induced by head-down bed rest.
abstract: BACKGROUND
  The aim of this study was to investigate the consequences of 20 d of physical inactivity using head-down bed rest (HDBR) at -6 degrees on leptin, ghrelin, and counter-regulatory hormone responses.
  
  
  METHODS
  Eight male volunteers were subjected to HDBR for 20 d. Variables measured before, during, and after HDBR included plasma cortisol, insulin, glucose, leptin, ghrelin, thyroid stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3).
  
  
  RESULTS
  No changes in ghrelin and leptin concentrations were observed during HDBR. Glucose concentration decreased significantly on the 20th day of HDBR compared to the pre-value (day 0) of HDBR (87.6 +/- 2.0 vs. 93 +/- 1.6 mg x dl(-1)). Significant correlation was observed between glucose and leptin concentrations.
  
  
  CONCLUSIONS
  The results provide the first evidence that 20 d of HDBR is not associated with an alteration in ghrelin concentration. Leptin, insulin, and cortisol concentrations did not differ during 20 d of HDBR.
authors.affiliation: Department of Physiology, Aichi Medical University School of Medicine, Nagakute, Japan. dominika@aichi-med-u.ac.jp
authors.forename: Dominika
authors.initials: D
authors.lastname: Kanikowska
authors.forename: Maki
authors.initials: M
authors.lastname: Sato
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iwase
authors.forename: Naoki
authors.initials: N
authors.lastname: Nishimura
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Yoko
authors.initials: Y
authors.lastname: Inukai
authors.forename: Junichi
authors.initials: J
authors.lastname: Sugenoya
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000704:Analysis of Variance; D015992:Body Mass Index; D054439:Ghrelin / Q000097:blood*; D005947:Glucose; D018475:Head-Down Tilt / Q000009:adverse effects*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood*; D008297:Male; D057185:Sedentary Behavior; D013223:Statistics as Topic; D011795:Surveys and Questionnaires; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D054439:Ghrelin; D007328:Insulin; D020738:Leptin; D014284:Triiodothyronine; D013972:Thyrotropin; D005947:Glucose; D013974:Thyroxine; D006854:Hydrocortisone