Dynamic Ghrelin and GH serum levels during combined simultaneous arginine clonidine stimulation test in children with dwarfism.

BACKGROUND: Combined simultaneous arginine clonidine stimulation (CSACS) test represents a more appropriate stimulus to detect Ghrelin, for it does not affect glucose metabolism.

METHODS: Fifty prepubertal children with dwarfism were recruited and further classified into normal growth hormone (NGH) and growth hormone deficiency (GHD) group with growth hormone (GH) peak cut-off value of 10 μg/l. In both groups, GH and Ghrelin serum levels were determined after the GH provocation test at 30, 60, and 120 min and the height standard deviation score (SDS) for bone age was measured six months later.

RESULTS: The participants were classified into NGH (n = 24) and GHD group (n = 26). A decrease in the circulating Ghrelin levels prior to the GH peak was observed in the NGH children, whereas both GH and Ghrelin levels demonstrated a rise in the GHD children. Ghrelin level in GHD group was higher compared with NGH group and the GH peak in GHD group is lower than NGH group. The 6 months CSACS treatment could increase the height SDS in both groups.

CONCLUSION: Although analogous changes were not detected in GHD group, the inverse correlation between GH and Ghrelin in NGH indicates a negative feedback lying between GH and Ghrelin.