EFFECT OF GROWTH HORMONE THERAPY ON VO2max, BODY COMPOSITION AND PHYSICAL DEVELOPMENT IN ADOLESCENTS.

Abstract

1477 This study examined the effects of growth hormone (GH) supplementation on VO2max, body composition and physical development in ten adolescents. Eight males and two females (mean age: 13.7±1.7yrs) that were normal variant of short stature were evaluated before (pre-GH) and after (post-GH) four months of subcutaneous GH therapy (0.05 mg·kg· day-1 x 6 days·week-1). Fat-free mass(FFM), fat mass and per cent (%) body fat were measured using Lunar Dual Energy X-ray Absorptiometry. VO2max was determined with a Bruce treadmill protocol using indirect open circuit calorimetry. Daily physical activity level of the subjects was constant throughout the therapy period. Differences between pre- & post-therapy responses were analyzed with a paired t-test. Results were: TableTableVO2max indexed to TBM and FFM increased (p<0.05) with GH therapy. Ht, TBM and FFM increased (p<0.05) from pre- to post-therapy. GH therapy also increased (p<0.05) IGF I. The IGF I served as a biochemical marker of physical growth and correlated positively with both FFM (r=0.46,p<0.05) and VO2max (r=0.54,p<0.05). The correlation between VO2max and FFM was r=0.68 (P<0.05). Results indicated that comparatively short term“pharmacological induced growth” was associated with an increase in IGF I, FFM and VO2max in developmentally restricted adolescents. The increase in VO2max that commonly occurs in conjunction with physical growth in pre-pubescent individuals may be linked to a developmentally indexed increase in fat free tissue and linear size.