GHRELIN CONCENTRATIONS IN NORMAL AND OBESE CHILDREN: ROLE OF PUBERTY.

Background and aims: Ghrelin is a peptide predominantly produced by the stomach that exerts a lot of central and peripheral activities such as endocrinological functions, orexigenic effect and control of energy expenditure, glucose homeostasis, reproduction, cardiovascular and anti-proliferative effects, influence on behavior and sleep. In particular, several studies showed that ghrelin is involved in the regulation of GH secretion and energy balance. Although several data has been published about ghrelin levels and its variations in childhood, the role of ghrelin on growth andmetabolismis still poorly understood. Aim of our study was to verify if during pubertal development obese children present the same pattern in ghrelin decreasing of normal weight children. Methods:We measured serum ghrelin, insulin and IGF-I in 130 schoolchildren aged 9.4±2.8 years.Height,weight,BMI and pubertal stages were also determined. Patients were divided in normal weight (N) (n=68) and obese (O) (n=62) children and then into three groups: stage 1, stages 2-3 and stages 4-5. Results: Ghrelin levels in obese (177.0; 143.0-298.0 pg/ml) were lower (p=0.0001) than in N children (344.5; 216.5-535.5 pg/ml). Insulin and leptin levels in obese were higher (p=0.0001) than in N children. Ghrelin levels progressively decreased from stage 1 to stages 4-5 both in normal and obese subjects (p=0.02 and p=0.001, respectively). Moreover, ghrelin was negatively correlated to insulin and IGF-I both in normal (p<0.05) and obese subjects (p<0.05). Conclusions: ghrelin levels during pubertal development show a clear decrease also in obese children, even if they start from lower ghrelin levels in infancy.