title: Short-term pharmacologically induced growth study of ontogenetic allometry of oxygen uptake in children.
abstract: BACKGROUND
  A range of allometric coefficients have been proposed in describing the maximal oxygen uptake (VO2max): body mass relation in children using weight-bearing ergometry. However, a wide deviation in the allometric coefficients for VO2max may be apparent when selected pediatric cohorts are studied in conjunction with clinical intervention for growth abnormalities.
  
  
  OBJECTIVE
  The purpose of this study was to determine the allometric coefficients for VO2max after short-term pharmacologically induced growth in pre- and early pubescent children.
  
  
  METHODS
  The treatment group consisted of nine subjects with non-growth hormone (GH)-deficient short stature and one with GH-deficient short stature (mean age: 13.7+/-1.7 years). Ten pre- and early pubescent children matched for age, height, weight, VO2max and body mass index (BMI) were controls. The treatment group were evaluated before (Pre-GH) and after (Post-GH) 4 months of subcutaneous GH therapy (0.05 mgkg(-1)day(-1) x 6 days week(-1)).
  
  
  RESULTS
  The mean ontogenetic coefficient for the treatment group was 1.50+/-0.20 and for the control group was 0.77+/-0.34. The mean allometric coefficient for body mass relative to VO2max was significantly higher in the treatment group compared with the control group (p<0.05). Height, weight, fat free mass (FFM), VO2max indexed to body mass (mLkg(-1)min(-1)) and FFM (mLkgFFM(-1)min(-1)) increased (p<0.05) with GH therapy. GH therapy also increased insulin-like growth factor-I (IGF-I) and served as a biochemical marker of GH therapy (p<0.05). The control group had no significant differences in all the variables tested (p<0.05).
  
  
  CONCLUSIONS
  The scaling for oxygen uptake (VO2) for body mass varies with GH treatment and the increase in VO2max that commonly occurs in conjunction with physical growth in the pre-and early pubescent individual may be linked to an increase in FFM and linear size.
authors.affiliation: Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pennsylvania 15261, USA. bala@hgen.pitt.edu
authors.forename: Govindasamy
authors.initials: G
authors.lastname: Balasekaran
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Robertson
authors.forename: Fredric L
authors.initials: FL
authors.lastname: Goss
authors.forename: Chittiwat
authors.initials: C
authors.lastname: Suprasongsin
authors.forename: Kapriel
authors.initials: K
authors.lastname: Danadian
authors.forename: Victor
authors.initials: V
authors.lastname: Govindaswamy
authors.forename: Silva A
authors.initials: SA
authors.lastname: Arslanian
mesh_terms: D000293:Adolescent; D001837:Body Weights and Measures; D002648:Child; D005260:Female; D006128:Growth / Q000187:drug effects* / Q000502:physiology*; D006130:Growth Disorders / Q000188:drug therapy*; D013006:Growth Hormone / Q000172:deficiency; D019382:Human Growth Hormone / Q000627:therapeutic use*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D011994:Recombinant Proteins
chemical_list: D011994:Recombinant Proteins; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D010100:Oxygen