Serum levels of growth hormone-binding protein and insulin-like growth factor-I during puberty.
OBJECTIVE
The aim was to investigate the effect of pubertal development on serum levels of growth hormone binding protein (GHBP) and IGF-I, and to study the relationship between GHBP levels and height standard deviation score (SDS), nutritional state and IGF-I levels.


METHODS
The investigation was performed on serum samples from 72 healthy adolescents of different pubertal stage. Results were compared to those obtained in 46 prepubertal children.


METHODS
Serum levels of GHBP were measured by HPLC gel filtration and IGF-I levels were measured by RIA after acid-ethanol extraction.


RESULTS
No effect of pubertal stage on serum levels of GHBP was found. A positive relationship was found between serum levels of GHBP and height SDS (r = 0.38; P < 0.005) and weight expressed as percentage of median weight for height age (r = 0.46; P < 0.0005). Serum levels of IGF-I increased during puberty and were not correlated with height SDS or weight for height age. In pubertal subjects, no relationship existed between serum levels of GHBP and IGF-I. In prepubertal subjects, however, a significantly positive relationship between GHBP and IGF-I levels (r = 0.66; P < 0.0005) was found.


CONCLUSIONS
Pubertal development does not seem to influence serum levels of GHBP. Height SDS and nutritional state are related to the concentration of GHBP. Before puberty, the level of GHBP is positively related to IGF-I levels; during puberty, however, the increase in serum IGF-I levels is not accompanied by changes in the amount of circulating GHBP.
Massa
G
G
Department of Paediatrics, University of Leuven, Belgium.
Bouillon
R
R
Vanderschueren-Lodeweyckx
M
M
D000293:Adolescent; D000328:Adult; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002352:Carrier Proteins / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D003430:Cross-Sectional Studies; D005260:Female; D013006:Growth Hormone / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D009752:Nutritional Status / Q000502:physiology; D011627:Puberty / Q000097:blood*; D011863:Radioimmunoassay
D002352:Carrier Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone