ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2008) 16 P352

Evaluation of insulin sensitivity in growth hormone (GH) deficient children before and at the end of rhGH therapy

Silvia Savastio1, Simonetta Bellone1, Jaele Bellone1, Fiorella Zanetta1, Giuseppina Di Dio1, Sara Giacoma1, Antonella Petri1, Flavia Prodam1, Ginevra Corneli1, Gianni Bona1 & Gianluca Aimaretti2

1Division of Pediatrics, University of Piemonte Orientale, Novara, Italy; 2Division of Endocrinology, Department of Clinical and Experimental Medicine, University of Piemonte Orientale, Novara, Italy.

Introduction: Therapy with recombinant GH (rhGH) allows GH-deficient children (GHD) to reach an adequate adult stature. Previous studies have reported a significant rise in serum insulin levels during GH therapy. It has been demonstrated that insulin resistance is a risk factor for the development of DMT2, atherosclerosis, dyslipidemia and hypertension.

Subjects and methods: Aim of our study was to evaluate changes in insulin sensitivity in a group of GHD children longitudinally followed during rhGH treatment. We measured fasting glucose and insulin levels and after oral glucose tolerance test (OGTT) in 11 GHD children (seven males and four females) at three times: 1) before starting of GH therapy (BT); 2) during the last year of therapy (T1); 3) 6 months (T6) after stopped therapy. At BT children presented age of 9.2±0.7 years, height SDS −1.9±0.2, while during T1 age was 15.4±0.3 years, height SDS −1.2±0.2. GH treatment was administered subcutaneously at a mean dosage of 0.2–0.3 mg/kg per week.

Results: No children showed impaired glucose tolerance or DMT2 during the therapy. Basal glucose levels were similar among the three times. Glucose levels in response to OGTT were statistically higher at T1 compared to BT and T6 (P<0.007). Fasting and during OGTT insulin levels were higher at T1 compared to BT and T6 (P<0.03). HOMA-IR index at T1 was higher compared to BT and T6 (P<0.03). Insulin sensitivity index as ISI was lower at T1 compared to BT and T6 (P<0.01).

Conclusions: Insulin sensitivity decreased during rhGH therapy, even if without the onset of impaired glucose tolerance, and was restored after stopping treatment. It remains to be clarified if this variation of insulin sensitivity during and after rhGH treatment could be related to changes in body composition and pubertal development or to rhGH treatment itself.