Changes of Insulin-like Growth Factor- I, Insulin-like Growth Factor Binding Protein-3 and 24-hour Urinary Growth Hormone in PrepubertalChildren with Insulin Dependent Diabetes Mellitus

Shin, Choong Ho; Yang, Sei Won

Abstract

BACKGROUND: The growth hormone - insulin-like growth factor-I(GH/IGF-I) axis and the insulin nutrition axis constitute two major anabolic hormone systems that interact at varous levels. It is well established that patients with type 1 diabetes mellitus have elevated GH levels and inappropriate low IGF-I for high GH levels. Such a deranged GH/IGF-I axis may complicate the somatic growth of children with diabetes. The purpose of this study assess the nature of deranged GH/IGF-I axis and the effect on somatic growth.
METHODS
In the present study, serum levels of IGF-I and IGFBP-3 were measured in 31 prepubertal children with type 1 DM (age, 8.93.1yr) and were compared with those levels in children with normal short stature (control) (age, 8.4+/-2.5 yr). RESULTS: In diabetic patients, age-adjusted serum levels of IGF-I and IGFBP-3 were significantly lower than those in controls (p<0.05). The difference of serum levels of IGF-I and IGFBP-3 between diabetic patients and control increased with chronologic age. There was no difference in 24-h urinary GH (24-h uGH) excretion between diabetic patients and normal controls. Simple regression analysis reveled no correlation between height SDS (standard deviation score)and HbA, (average 7.4%), IGF-I, IGFBP-3, urinary growth hormone, and chronological age. But height SDS had a tendency to decrease with the duration of diabetes, but without statistical significance. In diabetic patients, the 24-h uGH expressed as ng/24 h was correlated with chronologic age, IGF-I, and IGFBP-3, but such correlation was not obsc:rved when the 24-h uGH was expressed as ng/g creatinine In the control group, the 24-h u(GH was expressed as ng/24 h, correlated with only IGFRP-3.
CONCLUSION
The growth impairment during puberty (which may be dependent on the degree of blood glucose control), rather than during prepuberty is probably responsible for the reduced final adult height in diabetic patients. This might be partly due to a relatively good blood glucose ontrol during prepubertal period. More importantly, it is suggested that this reduced final adult height comes from a gradual decrease in IGF-I and IGFBP-3 levels for long period during diabetes, regardless of the 24-h urinary growth hormone excretion.