Correlation Between Insulin-Receptor Binding and Insulin Resistance Measured By the Homeostasis Model Assessment

ABSTRACT
The study was designed to investigate the correlation between insulin-receptor binding and insulin resistance in obesity, type 2 diabetes mellitus and in a group of healthy normal-weight subjects. 121 subjects were enrolled in the study - 32 subjects with different degrees of obesity (mean age 44.1±12.1 years); 43 newly-diagnosed type 2 diabetic patients (mean age 49.8±9.5 years) and 46 healthy controls (mean age 47.7±10. 8 years). Insulin-receptor binding was studied on circulating mononuclear blood cells. Results are presented as the number of total and high-affinity receptors per cell and receptor affinity. Insulin resistance was estimated using the homeostasis model assessment (HOMA-IR). We found a significant negative correlation between the total number of insulin receptors per cell and HOMA-IR (r=-0.71, p<0.0001) and the number o f high-affinity insulin receptors and HOMA-IR (r=-0.61, p=0.001) and no correlation between receptor affinity and HOMA-IR (r=0.07, p>0.1) in the whole study population. When analysing the groups separately we found the strongest correlation between insulin receptors and HOMA-IR in the obese subjects (r=-0.84, p<0.0001) compared with the type 2 diabetic patients (r=-0.58, p=0.001) and the healthy controls (r=-0.51, p=0.001) . Our results demonstrate that there is a significant correlation between the number of insulin receptors, measured on mononuclear blood cells, and insulin resistance estimated by HOMA index in type 2 diabetic patients, in obese subjects and in healthy controls.