IngentaConnect Serum levels of free insulin-like growth factor (IGF)-I and IGF-b...

Abstract:

OBJECTIVE

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).

SUBJECT

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 µg/l after two standard provocation tests.

RESULTS

The serum levels of free IGF-I were significantly lower in short children (1·6 ± 0·3 µg/l) than in the controls (2·8 ± 0·6 µg/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 µg/l) than in controls (80·0 ± 8·7 µg/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.

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