Abstract

Introduction: The high-molecular weight (HMW) form of adiponectin is reported to be the most active form of this hormone and current data reveals decreased plasma HMW adiponectin levels to be associated with insulin resistance. This study was intended to investigate the effect of exercise intensity on plasma HMW adiponectin concentrations. Materials and Methods: Thirty-two eight week-old male Wistar rats (185±50 g) were randomly assigned to one of four groups as follows: High intensity (HI: 34m/min ~%80-%85 VO2max), moderate intensity (MI: 28m/min ~ %70-%75 VO2max), low intensity (LI: 20m/min ~%50-%55 VO2max), and the sedentary control (SED) groups. All experimental groups performed a 12 week exercise program, including treadmill running on a 0˚ slope for 1 hr/day, 5 days/week. Fasting levels of circulating HMW adiponectin, testosterone, and insulin resistance index (HOMA-IR) were measured after the exercise program and, data were analyzed using one-way ANOVA, with Pearson's correlation was used to identify any possible relationship among the assessed variables. Results: HMW adiponectin plasma concentrations increased significantly in the HI and MI exercise training groups (p<0.05). HMW adiponectin was also found to be inversely related to HOMA-IR (r = -0.37, p=0.003), insulin (r= -0.46, p=0.008) and testosterone (r = -0.38, p=0. 03). Conclusion: It can be concluded that exercise intensity appears to be an important parameter in increasing plasma HMW adiponectin levels in healthy male rats.