title: Phosphorous magnetic resonance spectroscopy-based skeletal muscle bioenergetic studies in subclinical hypothyroidism.
abstract: BACKGROUND
  Subclinical hypothyroidism (sHT) is considered to be a milder form of thyroid dysfunction. Few earlier studies have reported neuromuscular symptoms as well as impaired muscle metabolism in sHT patients.
  
  
  OBJECTIVE
  In this study we report our findings on muscle bioenergetics in sHT patients using phosphorous magnetic resonance spectroscopy (31P MRS) and look upon the possibility to use 31P MRS technique as a clinical marker for monitoring muscle function in subclinical thyroid dysfunction.
  
  
  METHODS
  Seventeen normal subjects, 15 patients with sHT, and 9 patients with hypothyroidism performed plantar flexion exercise while lying supine in 1.5 T magnetic resonance scanner using custom built exercise device. MR Spectroscopy measurements of inorganic phosphate (Pi), phosphocreatine (PCr), and ATP of the calf muscle were taken during rest, at the end of exercise and in the recovery phase. PCr recovery rate constant (kPCr) and oxidative capacity were calculated by monoexponential fit of PCr vs time (t) at the beginning of recovery.
  
  
  RESULTS
  We observed that changes in some of the phosphometabolites (increased phosphodiester levels and Pi concentration) in sHT patients which were similar to those detected in patients with hypothyroidism. However, our results do not demonstrate impaired muscle oxidative metabolism in sHT patients based upon PCr dynamics as observed in hypothyroid patients.
  
  
  CONCLUSIONS
  31P MRS-based PCr recovery rate could be used as a marker for monitoring muscle oxidative metabolism in sub clinical thyroid dysfunction.
authors.affiliation: NMR Research Centre, Institute of Nuclear Medicine and Allied Sciences, Delhi, India.
authors.forename: P
authors.initials: P
authors.lastname: Rana
authors.forename: G
authors.initials: G
authors.lastname: Sripathy
authors.forename: A
authors.initials: A
authors.lastname: Varshney
authors.forename: P
authors.initials: P
authors.lastname: Kumar
authors.forename: M Memita
authors.initials: MM
authors.lastname: Devi
authors.forename: R K
authors.initials: RK
authors.lastname: Marwaha
authors.forename: R P
authors.initials: RP
authors.lastname: Tripathi
authors.forename: S
authors.initials: S
authors.lastname: Khushu
mesh_terms: D000328:Adult; D058070:Asymptomatic Diseases; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000175:diagnosis / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism*; D010725:Phosphocreatine / Q000032:analysis / Q000378:metabolism; D010758:Phosphorus / Q000032:analysis; D020127:Recovery of Function / Q000502:physiology; D012146:Rest / Q000502:physiology; D055815:Young Adult
chemical_list: D010725:Phosphocreatine; D010758:Phosphorus