Adiponectin is not altered with exercise training despite enhanced insulin action

Abstract

Adiponectin is an adipocytokine that is hypothesized to be involved in the regulation of insulin action. The purpose of the present investigation was to determine whether plasma adiponectin is altered in conjunction with enhanced insulin action with exercise training. An insulin sensitivity index (SI) and fasting levels of glucose, insulin, and adiponectin were assessed before and after 6 mo of exercise training (4 days/wk for ∼45 min at 65–80% peak O2 consumption) with no loss of body mass (PRE, 91.9 ± 3.8 kg vs. POST, 91.6 ± 3.9 kg) or fat mass (PRE, 26.5 ± 1.8 kg vs. POST, 26.7 ± 2.2 kg). Insulin action significantly ( P < 0.05) improved with exercise training (SI +98%); however, plasma adiponectin concentration did not change (PRE, 6.3 ± 1.5 μg/ml vs. POST, 6.6 ± 1.8 μg/ml). In contrast, in a separate group of subjects examined before and after weight loss, there was a substantial increase in adiponectin (+281%), which was accompanied by enhanced insulin action (SI, +432%). These data suggest that adiponectin is not a contributory factor to the exercise-related improvements in insulin sensitivity.

Relationships of physical activity with metabolic syndrome features and low-grade inflammation in adolescents

“…However, the present results suggest that they do not directly account for the beneficial effects of physical activity on insulin resistance and IL-6 plasma levels. The absence of a relationship between physical activity and adiponectin levels is in agreement with intervention studies in which adiponectin was not affected by a training programme [38,39]. An inverse relationship between physical activity and TNF-α or sTNF-α R1 has been reported but could require high-intensity activities [13].…”

Adiponectin, insulin resistance and clinical expression of the metabolic syndrome in patients with Type 2 diabetes

“…26,27 Although we have shown an inverse association between adiponectin and insulin resistance, it is obvious from Figure 2a that there was overlap of adiponectin levels between insulin-sensitive and insulinresistant patients and some of the insulin-sensitive individuals had low adiponectin. Some other studies have reported similar disassociation between adiponectin levels and insulin resistance 28,29 and the relationship between adiponectin and IR is probably not one of the direct cause and effect in all patients. It is possible that their inverse relationship may be mediated not only by insulin levels but also by other hormones such as catecholamines or androgens, [30][31][32] as well as by pro-inflammatory cytokines, 33,34 and some medications.…”

Reduced plasma adiponectin concentrations may contribute to impaired insulin activation of glycogen synthase in skeletal muscle of patients with type 2 diabetes

“…In addition, reduced basal lipid oxidation in muscle, metabolic inflexibility and lower plasma adiponectin levels in type 2 diabetes and obesity are not reflected in lower AMPK activity or altered protein expression of AMPK isoforms in vivo compared with healthy lean subjects [26][27][28]. Moreover, exercise-induced improvement of insulin sensitivity, which is associated with increased AMPK activity in both healthy and type 2 diabetic subjects [28,45], is not paralleled by increased plasma adiponectin [46,47]. Thus, there is no simple relationship between plasma adiponectin, AMPK activity and insulin sensitivity in skeletal muscle, and further studies are needed to establish the role of adiponectin in metabolic flexibility and mitochondrial function, and to what extent AMPK is involved.…”