Obesity is associated with impaired insulin-mediated potassium uptake

The ability of insulin to promote extrarenal potassium uptake and to stimulate glucose uptake was examined in eight obese and ten normal weight control subjects. Insulin was infused at three rates to produced plasma insulin concentrations of approximately 100, 1,900, and 19,000 microU/mL. Insulin-mediated potassium, as well as glucose uptake, was diminished during the lowest dose insulin clamp study (100 microU/mL) but could be normalized at pharmacologic plasma insulin concentrations. These results indicate that obese subjects are resistant to the ability of insulin to stimulate potassium uptake by extrarenal tissues. Impaired potassium uptake at physiologic plasma insulin levels, with normalization at supraphysiologic insulin concentrations, is most consistent with a decrease in the number of insulin receptors on insulin target tissues.