Serum levels of free insulin-like growth factor (IGF)-I and IGF-binding protein-1 in prepubertal children with idiopathic short stature

Clin Endocrinol (Oxf). 2000 Dec;53(6):683-8. doi: 10.1046/j.1365-2265.2000.01145.x.

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.

MeSH terms

  • Case-Control Studies
  • Child
  • Child, Preschool
  • Female
  • Growth Disorders / blood*
  • Growth Hormone / blood
  • Humans
  • Insulin / blood
  • Insulin-Like Growth Factor Binding Protein 1 / blood*
  • Insulin-Like Growth Factor Binding Protein 3 / blood
  • Insulin-Like Growth Factor I / analysis*
  • Male
  • Pituitary Function Tests
  • Regression Analysis

Substances

  • Insulin
  • Insulin-Like Growth Factor Binding Protein 1
  • Insulin-Like Growth Factor Binding Protein 3
  • Insulin-Like Growth Factor I
  • Growth Hormone