title: Serum levels of free insulin-like growth factor (IGF)-I and IGF-binding protein-1 in prepubertal children with idiopathic short stature.
abstract: The study was performed to evaluate the relationships among serum free and total insulin-like growth factor (IGF)-I, IGF-binding protein-1 (IGFBP-1), IGFBP-3, and insulin concentrations in prepubertal children with idiopathic short stature (ISS). Eighteen children with ISS and 15 age-matched controls were included in the study. All short children had a height standard deviation score of more than 2 below the mean, and maximum stimulated GH levels greater than 10 microg/l after two standard provocation tests. The serum levels of free IGF-I were significantly lower in short children (1.6 +/- 0.3 microg/l) than in the controls (2.8 +/- 0.6 microg/l, P<0.05), while total IGF-I levels were slightly, but not significantly, lower in short children than in controls. The serum levels of IGFBP-1 were significantly higher in the ISS group (124.6 +/- 5.6 microg/l) than in controls (80.0 +/- 8.7 microg/l, P < 0.0001). The fasting insulin and IGFBP-3 levels were similar in both groups. A stepwise regression analysis for all subjects revealed that IGFBP-1 is the only independent predictor of log free IGF-I (R2 = 0.23, P<0.01). The present study shows that the serum levels of free IGF-1 are significantly lower and insulin-like growth factor-binding protein-1 levels are higher in prepubertal children with idiopathic short stature, as compared with age-matched controls. The high IGFBP-1 may contribute to growth retardation in a subgroup of idiopathic short stature through a decrease in free IGF-1.
authors.affiliation: Department of Paediatrics, University of Tsukuba, Ibaraki Children's Hospital, Ibaraki, Japan. tkamoda@md.tsukuba.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Kamoda
authors.forename: H
authors.initials: H
authors.lastname: Saitoh
authors.forename: T
authors.initials: T
authors.lastname: Hirano
authors.forename: A
authors.initials: A
authors.lastname: Matsui
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006130:Growth Disorders / Q000097:blood*; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D010901:Pituitary Function Tests; D012044:Regression Analysis
chemical_list: D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone