Plasma Adiponectin Concentration Is Associated With Skeletal Muscle Insulin Receptor Tyrosine Phosphorylation, and Low Plasma Concentration Precedes a Decrease in Whole-Body Insulin Sensitivity

Adiponectin, the most abundant adipose-specific pro-tein, has been found to be negatively associated with degree of adiposity and positively associated with insu-lin sensitivity in Pima Indians and other populations. Moreover, adiponectin administration to rodents has been shown to increase insulin-induced tyrosine phosphory-lation of the insulin receptor (IR) and also increase whole-body insulin sensitivity. To further characterize the relationship between plasma adiponectin concentra-tion and insulin sensitivity in humans, we examined 1) the cross-sectional association between plasma adi-ponectin concentration and skeletal muscle IR tyrosine phosphorylation and 2) the prospective effect of plasma adiponectin concentration at baseline on change in insulin sensitivity. Fasting plasma adiponectin concen