The impact of growth hormone replacement therapy on adipokines, but not upon ghrelin.

Background: Besides growth acceleration, growth hormone (GH) therapy of GH deficient (GHD) children improves body composition by decreasing body fat. This effect is due to GH interaction with lipid and carbohydrate metabolism, possibly also mediated by adipokines secreted by adipose tissue, and ghrelin. This study aimed to assess the impact of one-year GH replacement therapy on the metabolic profile, adipokines, and acylated/unacylated ghrelin of prepubertal children with GHD.

Methods: Prospective observational study of 42 non-obese, prepubertal children with GHD followed up for twelve months. Mean lipid, carbohydrate, adipokine profiles, acylated/unacylated ghrelin, and body composition data before therapy onset were compared with measurements obtained after 6 and 12 months of GH therapy.

Results: Total body fat content and body fat percentage decreased significantly, while the lipid profile improved over the study period in the 42 GHD children with a mean age of 9.2±2.6 years. The levels of leptin and unacylated ghrelin decreased significantly, whereas adiponectin and acylated ghrelin values increased after GH therapy. In regression analysis models, GH treatment (reflected by increased absolute values or standard deviations of IGF1) influences the variation of leptin and adiponectin, but not ghrelin, independently of body composition - lean or fat mass.

Conclusions: GH replacement therapy improves body composition, lipid, and adipokine profile in GHD children. Also, GH replacement therapy directly impacts leptin and adiponectin concentrations, independently of body composition. Further research is needed to identify the molecular mechanisms and metabolic pathways by which the GH/IGF1 axis influences adipokines secretion.