Serum Levels of IGF-I and IGFBP-3 in Prepubertal and Pubertal Children with Type I Diabetes Mellitus

Abstract:

OBJECTIVE: To study serum insulin like growth factor I (IGF-I) and IGF-I binding protein 3 (IGFBP-3) in children with type I diabetes mellitus (DM) and to explore the relationship between GH IGF-I axis and blood sugar. METHODS: ELISA and immunoradioassay were used respectively for IGF-I and IGFBP-3 determination in 63 children with type I DM and 47 normal children. RESULTS: ①Before puberty, there was no statistical difference in serum levels of IGF-I and IGFBP-3 between the diabetic group and control group; but in puberty, serum levels of IGF-I［(178.2±65.9) ng/ml］ and IGFBP-3［(2 956.0±847.6) ng/ml］ in the diabetic group were significantly lower than those of the control group ［(229.6±54.5) ng/ml, (3 393.2±748.9) ng/ml］(P<0.01 or 0.05). ② Serum levels of IGF-I andIGFBP-3 ［(143.0±67.5) and (2 740.0±449.8) ng/ml］ were elevated in children with recent onset type I DM after insulin therapy compared with the pre treatment group ［(54.8±44.3) and (2 233.8±336.2) ng/ml］(P<0.05). ③ In the diabetic group, HbA IC was negatively correlated to serum levels of IGF-I (r=-0.32, P<0.01) and IGFBP-3 (r=-0.29, P<0.05). ④ In the diabetic group, HbAIC and insulin dose in puberty were higher than those in prepuberty ［(9.0±1.8)% vs (7.8±1.8)%, (0.86±0.30) U/kg vs (0.64±0.38) U/kg］(P<0.05). CONCLUSIONS: Serum levels of IGF-I and IGFBP-3 decrease in children with type I DM, especially during puberty. This suggests that GHIGF-I axis is severely disturbed in these adolescents, probably an important cause of poor blood sugar control.