Study on circulating levels of ghrelin and obestatin in human simple obesity

AIM To investigate preprandial and postprandial changes of circulating ghrelin and obestatin levels in simple obesities. METHODS Plasma ghrelin and obestatin concentrations 1 hour before meal were measured by radioimmunoassay in 16 simple obese adolescents and 14 normal controls. Body mass index, waist-hip ratio, plasma glucose, plasma insulin, blood lipids, white blood cells count and high sensitive C-reactive protein were measured. Plasma ghrelin and obestatin concentrations 2 hours after meal were measured in 10 of the simple obese adolescents and 10 of the controls. RESULTS Although both prepramdial plasma ghrelin (P<0.01) and obestatin (P<0.05) concentrations decreased in simple obesities as compared with those in normal controls (both P<0.01), their ratios of ghrelin to obestatin were increased (P<0.01) even after adjustment for gender and age. The ratios of postprandial ghrelin to postprandial obestatin decreased both in simple obesities (P<0.05) and normal controls (P<0.01) compared with their preprandial ratios, but the postprandial ratios were similar between simple obesities and normal controls. There were significant positive correlations respectively between prepramdial ghrelin/obestatin and BMI (r=0.54, P<0.01), waist circumference (r=0.39, P<0.05), total cholesterol (r=0.40, P<0.05), low-density lipoprotein cholesterol (r=0.41, P<0.05). CONCLUSION The imbalance of prepramdial circulating ghrelin and obestatin may play a role in the pathogenesis of human obesity.