title: Changes in skeletal muscle and body composition after discontinuation of growth hormone treatment in growth hormone deficient young adults.
abstract: OBJECTIVE
  The aim of this study was to determine whether there are any changes in skeletal muscle strength and size and body composition following growth hormone (GH) withdrawal in GH deficient young adults.
  
  
  METHODS
  A longitudinal, 1-year, open, uncontrolled study of the changes in skeletal muscle and body composition following GH withdrawal was performed. Endocrine status was reassessed at the end of the study period during an insulin tolerance test. Some measurements were repeated after 2 years of treatment.
  
  
  METHODS
  Twelve (11 male, one female; age range 14-21) patients who had been diagnosed during childhood as growth hormone deficient took part in the study. Four of the 12 patients were found to have a normal GH response on retesting at the end of the study and their results were analysed as a separate group.
  
  
  METHODS
  Quadriceps and forearm flexor maximum voluntary isometric strength, body fat content and serum IGF-1 were measured at 3-monthly intervals over 1 year. Every 6 months muscle size was measured from computerized tomography scans and fibre area from quadriceps needle biopsy samples.
  
  
  RESULTS
  For the growth hormone deficient group the 12 month quadriceps strength, size and fibre areas were 94.0% +/- 8.5 (mean +/- SD), 94.5% +/- 6.3 and 85.6% +/- 17.7 respectively of control (baseline) values. Forearm flexor strength and size were 101.4% +/- 7.9 and 92.0% +/- 9.2 of control. Body fat percentage had increased from 19.5% +/- 8.6 to 24.1% +/- 9.5. No change was seen in the non-growth hormone deficient group.
  
  
  CONCLUSIONS
  Although the changes measured were relatively small they suggest a role for GH in the maintenance of muscle integrity and body composition in the young adult with growth hormone deficiency.
authors.affiliation: Department of Medicine, University College, London, UK.
authors.forename: O M
authors.initials: OM
authors.lastname: Rutherford
authors.forename: D A
authors.initials: DA
authors.lastname: Jones
authors.forename: J M
authors.initials: JM
authors.lastname: Round
authors.forename: C R
authors.initials: CR
authors.lastname: Buchanan
authors.forename: M A
authors.initials: MA
authors.lastname: Preece
mesh_terms: D000293:Adolescent; D000328:Adult; D001823:Body Composition / Q000187:drug effects*; D005260:Female; D006130:Growth Disorders / Q000097:blood / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D013006:Growth Hormone / Q000172:deficiency* / Q000627:therapeutic use; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors
chemical_list: D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone