The pathogenesis of insulin resistance is not completely understood, however, there are data that it might be associated with altered tissue carbohydrate and lipid oxidation. Adiponectin may be a key regulator of insulin sensitivity and energy metabolism. The aim of the present study was to determine the association of adiponectin, glucose metabolism (oxidation and storage) and lipid oxidation by applying the euglycemic clamp technique and indirect calorimetry.
The study was carried out on 68 young (age 26.38±6.82 yr (mean±S.D.), BMI: 29.15±7.24 kg/m2 (mean±S.D.)) people. Anthropometric and biochemical parameters were measured and oral glucose tolerance test was performed. Plasma adiponectin was measured with radioimmunoassay (RIA) kit. Insulin sensitivity was evaluated with the euglycemic hyperinsulinemic clamp technique. Whole-body fat and carbohydrate oxidation was measured by indirect calorimetry at baseline (in the fasting state) and during last 30 minutes of the clamp. Nonoxidative glucose disposal rate was calculated by subtracting glucose oxidation rate from GDR.
Plasma adiponectin was positively related to insulin sensitivity (r=0.477, P=0.000038), glucose oxidation at the steady state (r=0.326, P=0.006) and non-oxidative glucose metabolism (r=0.424, P=0.0003) and was negatively associated with FFA at the end of the clamp and fat oxidation during hyperinsulinemia (r=−0.0309, P=0.0137 and r=−0.260, P=0.031). Insulin sensitivity was positively related to fat oxidation during fasting (r=0.241, P=0.04) and carbohydrate oxidation during last 30 minutes of the clamp (r=0.308, P=0.001).
We conclude that adiponectin modulates insulin sensitivity probably through influencing both oxidative and non-oxidative glucose metabolism.