Plasma Ghrelin Levels and Its Relationship with Obesity in Obese Children

Jo, Dae Sun; Lee, Jae Un; Kim, Sun Young; Kim, Sun Jun; Kang, Chang Won; Hwang, Pyoung Han; Lee, Dae Yeol

Abstract

Background
Ghrelin is a new endogenous ligand for the growth hormone secretagogue receptor. It activates the release of growth hormone from the pituitary and it also participates in the regualtion of energy homeostasis. The aims of the study were to characterize the changes in plasma ghrelin levels in obese subjects compared with lean control or overweight subjects, and their relationship to various parameters in obese subjects.
METHODS
In this study, 121 elementary school children were divided into 3 groups according to their body mass index (BMI). The lean control subjects consisted of 28 children who had less than 85 percentile of BMI. The overweight subjects consisted of 22 children who had 85-95 percentile of BMI. The obese subjects consisted of 71 children who had over 95 percentile of BMI. All subjects in 3 groups were evaluated according to their age, height, weight, obesity index, plasma ghrelin, serum lipid, glucose and insulin levels. Leu72Met mutation of prepro-ghrelin gene was directly detected by digesting the PCR fragments with Bsrl.
RESULTS
Among antropometric data, body weight, BMI and obesity index were higher in obesity and overweight subjects than those of lean control subjects (P<0.05). The plasma ghrelin levels were significantly lower in overweight and obese subjects (P<0.05). In addition, serum triglyceride and LDL cholesterol levels were significantly higher in these groups compared to the control subjects (P<0.05). The concentrations of plasma ghrelin were significantly negatively correlated with BMI, obesity index, serum triglyceride, LDL cholesterol and insulin in all the children. However, there was no significant relationship between plasma ghrelin levels and any various parameters in obese subjects. Leu72Met mutation was detected in about 30% of obese children. However, we could not find any differences between lean control and obese children.
CONCLUSION
We proved a significantly lower plasma ghrelin levels in overweight and obese subjects. Further studies are now needed to establish the role of ghrelin in the pathogenesis of human obesity.