Fasting Ghrelin Levels Are Decreased in Obese Subjects and Are Significantly Related With Insulin Resistance and Body Mass Index

BACKGROUND Ghrelin is a 28-amino acid peptide that predominantly produced by the stomach. Strong evidence indicates the effects of ghrelin in the regulation of metabolic functions and its potential role in the aetiology of obesity. AIM The aim of this study was to investigate the relationship of ghrelin levels with obesity, insulin resistance and glucose in normal and obese subjects. METHODS Thirteen normal (n = 13) and seven (n = 7) obese weight subjects aged 20-22 participated in the study. Fasting plasma ghrelin, insulin and glucose levels were measured after overnight fasting. HOMA-IR was calculated to evaluate insulin resistance. RESULTS Ghrelin and insulin levels were found to be statistically significantly lower and higher in obese subjects (P < 0.001), respectively. Glucose levels were clinically higher in obese subjects but not statistically significant. Fasting plasma ghrelin was negatively correlated with BMI (r = -0.77, P < 0.001), fasting insulin levels (r = -0.55, P < 0.001) and HOMA-IR (r = -0.66, P < 0.001). There was no correlation between ghrelin and glucose. In multiple regression analysis, insulin levels (Beta:-2.66, 95%CI:-2.49, -2.78, P < 0.001) HOMA-IR (Beta:-2.41, 95%CI:-2.33, -2.55, P < 0.001) and BMI (Beta:-1.77, 95%CI:-1.66, -1.89, P < 0.001) were significant independent determinants of fasting ghrelin. CONCLUSION Obese subjects have low fasting ghrelin levels that they are significantly related to insulin resistance and body mass index. More prospective studies are needed to establish the role of ghrelin in the pathogenesis of human obesity.