Effects of Growth Hormone Secretion with Insulin Induced Hypoglycemia and L-dopa in Children with Short Stature

Lee, So La; Kang, Chang Lang; Kim, Jong Duck

Abstract

PURPOSE
Insulin induced hypoglycemia and L-dopa are potent for growth hormone(GH) secretion in children. We evaluated the effects of GH secretion with insulin and L-dopa in 22 children with height percentile below 3 and 11 children with height percentile between 10 to 25.
METHODS
Thirty four children were performed GH secretion study after classified by height percentile and bone age according to their age and sex. Twenty two children are height percentile below 3 and bone age is delayed more than one years compare to chronologic age(group A). As a control group, twelve children took part in this study and their height percentile were between 10 to 25 but, bone age was not concerned(group B). Serum GH concentration and blood glucose level was detected on 0, 30, 60, and 90 minutes after insulin 0.1U/kg was injected intravenously. And then serum GH concentration was measured on 0, 30, 60, and 90 minutes after L-dopa 10mg/kg was administered orally. Serum GH was measured by radioimmunoassay.
RESULTS
GH level in group A was below 7ng/mL in 13 children(59%) after insulin and L-dopa administration respectively but in 11 children(50%) GH level were all below 7ng/mL after insulin and L-dopa adminstration. GH deficiency(7ng/mL) was detected only one children in group B. In Group A and B, peak GH concentration was noted on 30 minutes after insulin administration, but on 60 minutes after L-dopa, peak GH concentration appeared in group B. GH concentration in zero time to 90 minutes after L-dopa was steady increased in group A.
CONCLUSION
Anthropometric data such as height percentile and bone age are good for prediction of GH deficiency and if we use these data and GH secretory effects of insulin induced hypoglycemia and L-dopa, we can predict GH deficiency more accurately.