title: The relationships between pubertal development, IGF-1 axis, and bone formation in healthy adolescents.
abstract: 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.
authors.affiliation: Section of Adolescent Medicine, Department of Pediatrics, Hacettepe University Faculty of Medicine, 06100 Ankara, Turkey. nuraykanbur@hotmail.com
authors.forename: Nuray Oksüz
authors.initials: NO
authors.lastname: Kanbur
authors.forename: Orhan
authors.initials: O
authors.lastname: Derman
authors.forename: Erol
authors.initials: E
authors.lastname: Kinik
mesh_terms: 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
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D015675:Osteocalcin; D007334:Insulin-Like Growth Factor I; D000469:Alkaline Phosphatase