Short-term pharmacologically induced growth study of ontogenetic allometry of oxygen uptake in children.
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.
Balasekaran
Govindasamy
G
Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pennsylvania 15261, USA. bala@hgen.pitt.edu
Robertson
Robert J
RJ
Goss
Fredric L
FL
Suprasongsin
Chittiwat
C
Danadian
Kapriel
K
Govindaswamy
Victor
V
Arslanian
Silva A
SA
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
D011994:Recombinant Proteins; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D010100:Oxygen