Effect of long-term growth hormone treatment on carbohydrate metabolism in children with growth hormone deficiency.
OBJECTIVE: Growth hormone (GH) has well known effects on carbohydrate metabolism. We have evaluated the effects of long-term growth hormone (GH) therapy on carbohydrate metabolism in children with classical GH deficiency (GHD) or GH neurosecretory dysfunction (GHND). STUDY DESIGN: Glucose, insulin and C-peptide concentrations at baseline and during oral glucose tolerance test (OGTT) were measured before and after 18 and 36 months of GH therapy (0.6-0.8 IU/Kg/week in 6 evening doses) in 13 GHD and 7 GHND children (15 boys and 5 girls, 15 prepubertal and 5 early pubertal; age at diagnosis 2.11-13.1 y). RESULTS: Mean fasting insulin and C-peptide concentrations after 18 months were similar to the pretreatment values, while after 36 months they were significantly higher than before treatment. Fasting glucose concentrations were similar to pretreatment both after 18 and 36 months. The mean areas under the curve (AUC) during OGTT for glucose, insulin, and C-peptide were significantly increased after 18 and 36 months. There were no differences between GHD and GHND patients. During the treatment period 10 of the 15 prepubertal patients entered puberty. A significant increase of insulin and C-peptide concentrations occurred after 36 months of GH treatment in the patients that remained prepubertal during treatment as well as in those who were pubertal when treatment was started. In three of our patients GH treatment caused glucose intolerance, which resolved after 6-12 months of a normal calorie low-simple carbohydrate diet without requiring discontinuation of treatment. CONCLUSION: Our data show that long-term GH treatment in GH deficient children causes hyperglycaemia and increased insulin secretion. These effects may in some patients induce glucose intolerance, which is reversible with appropriate dietary measures and does not require discontinuation of treatment.