Objectives: To investigate the influence of body weight and sex on serum levels of insulin, leptin, ghrelin, IGF1, adiponectin and TSH.
Methods: Serum levels of insulin, IGF1, TSH and ghrelin were measured by RIA, leptin by IRMA and adiponectin by ELISA in 90 individuals (42 women, average age 49.8±8.9 years( 48 men, average age 49.1±6.6). The sample was divided into three subgroups: normal weight (BMI=15.524.9), excess weight (BMI=25.029.9) and obesity (BMI>30). Results were correlated to BMI, to each other and compared with the endothelium function. The Ethical Committee approval was obtained for the research in 2002.
Results: Serum levels of measured hormones were influenced by body weight in both sexes. The influence was stronger in the case of insulin, leptin and adiponectin in women and in the case of IGF1 in men. Serum levels of ghrelin were not influenced by sex. The highest serum levels of insulin and leptin and the lowest levels of adiponectin, ghrelin and IGF1 were found in individuals with BMI over 30. Positive correlation was confirmed between leptin and insulin (r=0.504, P=0.001). Negative correlation was observed between adiponectin and insulin (r=−0.377, P=0.02) and between adiponectin and leptin (r=−0.265, P=0.02). Subjects with endothelium dysfunction had higher BMI, insulin and leptin and lower ghrelin, adiponectin and IGF1. No correlation was found between TSH and BMI, sex, other examined hormones and the endothelium function.
Conclusions: Higher levels of leptin and lower levels of adiponection may increase the level of insulin. Higher levels of leptin lead to the decrease of ghrelin, which may enhance oxidative stress. Insulin resistance and obesity are main risk factors of the development of metabolic syndrome and process of atherosclerosis. Leptin, ghrelin, adiponectin and IGF may be considered as markers of metabolic syndrome and connected complications.