The relationships between pubertal development, IGF-1 axis, and bone formation in healthy adolescents.
As IGF-1 is the major factor that affects bone growth, and both osteocalcin and bone-specific alkaline phosphatase are important markers of bone formation during puberty, there must be a relationship between these markers that does not change according to sex. The aim of this study was to investigate the relationships between pubertal development, the IGF-1 axis, and bone formation in healthy adolescents. Two hundred and five healthy children and adolescents were included in this cross-sectional study. Tanner's classification was used to determine the pubertal developmental stage. Serum IGF-1 levels and IGF-1/IGFBP-3 ratios increased with advancing pubertal stages, and maximum mean values were found at stages III-IV in girls and at stage IV in boys. Serum IGF-1 and IGFBP-3 levels were significantly correlated with osteocalcin and bone-specific alkaline phosphatase levels in boys, but not in girls. This difference between the sexes, and the relation of the IGF-1 axis to increased bone formation during puberty in both sexes, can be explained by the rate of increase of the IGF-1/IGFBP-3 ratio. We conclude that the timing of the increased bone formation rate during puberty; that is, the timing of the pubertal growth spurt, is determined by the maximum increase rate of the IGF-1/IGFBP-3 ratio. But this new hypothesis needs to be supported by longitudinal studies.
Kanbur
Nuray Oksüz
NO
Section of Adolescent Medicine, Department of Pediatrics, Hacettepe University Faculty of Medicine, 06100 Ankara, Turkey. nuraykanbur@hotmail.com
Derman
Orhan
O
Kinik
Erol
E
D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D002648:Child; D005260:Female; D006262:Health; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010012:Osteogenesis / Q000502:physiology*; D011627:Puberty / Q000502:physiology*; D012727:Sex Characteristics
D018972:Insulin-Like Growth Factor Binding Protein 3; D015675:Osteocalcin; D007334:Insulin-Like Growth Factor I; D000469:Alkaline Phosphatase