Fasting and postprandial relationships among plasma leptin, ghrelin, and insulin in prepubertal obese children

Background: Leptin is involved in the long-term regulation of body weight and dietary intake, while ghrelin plays an essential role in appetite control. High levels of leptin have been associated with adiposity and the suppression of ghrelin levels with increased dietary intake. Aims: To evaluate fasting and postprandial concentrations of plasma leptin and ghrelin after intake of a standardised breakfast and to study the relationship of these hormones with adiposity and insulin resistance in obese prepubertal children. Methods: 34 obese and 20 normal-weight prepubertal children aged 6-12 years were selected. Plasma leptin and ghrelin were measured by ELISA and radioimmunoassay, respectively. The general linear model of variance, principal-component factor, and Pearson’s analyses correlation were performed. Results: Baseline and postprandial leptin levels were higher in obese versus normal-weight children. In obese, ghrelin showed an altered pattern during the postprandial period, recovering to baseline levels at 3 h after the intake. Insulin resistance was associated with leptin and independently with ghrelin. Conclusion: The association of ghrelin with insulin resistance provides further evidence on the regulation of ghrelin in glucose homeostasis in childhood obesity at the prepubertal age. Changes in ghrelin after dietary intake may be related to an earlier recovery of appetite in prepubertal obese children. (C) 2009 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.