Adiponectin Oligomers in Human Serum during Acute and Chronic Exercise: Relation to Lipid Metabolism and Insulin Sensitivity

Abstract

Beneficial effects of physical exercise include improved insulin sensitivity, which may be affected by a modulated release of adiponectin, which is exclusively synthesized in white adipose tissue and mediates insulin sensitivity. Adiponectin circulates in three different oligomers, which also have a distinct biological function. We therefore aimed to investigate the distribution of adiponectin oligomers in human serum in relation to physical activity. Thirty-eight lean and healthy individuals were investigated. Seven healthy women and 8 healthy men volunteered to investigate the effect of chronic exercise, at 3 different time points with different training intensities. These individuals were all highly trained and were compared to a control group with low physical activity (n = 15). For studying acute exercise effects, 8 healthy men participated in a bicycle test. Adiponectin was determined by ELISA, oligomers were detected by non-denaturating western blot. Total adiponectin and oligomers were unchanged by acute exercise. LDL cholesterol was significantly lower in the chronic exercise group (p = 0.03). Total adiponectin levels and oligomers were not different between these two groups and were unaltered by different training intensities. However, total adiponectin and specifically HMW oligomers correlated with HDL cholesterol (r = 0.459; p = 0.009). We conclude that acute and chronic exercise does not directly affect circulating adiponectin or oligomer distribution in lean and healthy individuals. Whether such regulation is relevant in individuals with a metabolic disorder remains to be determined. However, our data suggest that adiponectin oligomers have distinct physiological functions IN VIVO, and specifically HMW adiponectin is closely correlated with HDL cholesterol.

Effects of Aerobic Exercise on Lipid Profiles and High Molecular Weight Adiponectin in Japanese Workers

“…Blüher et al (27) found that HMW adiponectin concentration increased with exercise treatment even in subjects with normal glucose tolerance. In contrast, Bobbert et al (28) showed that HMW adiponectin concentration was similar before and after 6 weeks of marathon training without a reduction in body weight. In the present study, HMW adiponectin concentration increased in the exercise group, although this increase did not reach significance during the aerobic exercise program (Fig.…”

Circulating adiponectin and adiponectin receptor expression in skeletal muscle: effects of exercise

“…In a 120-min cycling program, healthy male subjects showed no significant changes in plasma adiponectin during the exercise program and throughout the post-exercise recovery period compared to baseline levels [85]. Furthermore, no significant changes in serum adiponectin or oligomer composition were observed following acute cycling in eight healthy men [86].…”

Effects of Supervised Aerobic Exercise Training on Serum Adiponectin and Parameters of Lipid and Glucose Metabolism in Subjects with Moderate Dyslipidemia

“…Previous reports from various protocol studies indicate that adiponectin levels do not change in healthy non-obese humans regardless of their improved insulin sensitivity, and suggest that a direct effect of exercise training on adiponectin levels is unlikely to represent the mechanisms of improved insulin resistance 8,[15][16][17] ; however, in insulin-resistant subjects, exercise training is recommended as a therapy to improve insulin resistance 18,19) , but previous studies in overweight and/or diabetic subjects have reported conflicting results 8,19,20) . The presence or absence of body weight loss after exercise training may not necessarily determine whether exercise training can increase serum adiponectin levels, but exercise training can exert a presumable effect on serum adiponectin levels in insulin-resistant and obese individuals through the reduction of fat mass with body weight loss 8,[20][21][22] .…”