Growth Hormone Response to GH-Releasing Peptide-2 in Children

Abstract

The insulin tolerance test (ITT) has been considered the most reliable test in the diagnosis of growth hormone deficiency (GHD), but it is contraindicated in some patients. Recently, the use of GH-Releasing Peptide-2 (GHRP-2) has been validated and reported as a safe and reliable test for the diagnosis of adult severe GHD. We evaluated the GH response to GHRP-2 in 56 children with growth disorders to assess its efficacy. A dose of 2 microg/kg of GHRP-2 was administered intravenously and serum GH concentrations were determined. The Spearman correlation coefficient for GH peak values indicated a favorable correlation with the ITT (P<0.0001). Peak GH concentrations were significantly (p<0.0001) lower in children with (median: 3.39 microg/l (ng/ml)) than without (25.10 microg/l (ng/ml)) GHD. In the analysis of sensitivity-specificity curves, the serum concentration at the point where sensitivity crosses specificity was 15 microg/l (ng/ml). The GHRP-2 test was safe and required only one hour or less, and was capable of diagnosing GHD in children.