Lymphocyte (Na,K) ATPase-dependent ⁸⁶Rb⁺ uptake in human obesity

Sodium and potassium ion-activated adenosinetriphosphatase (EC number 3.6.1.3) activity, measured as the uptake of ⁸⁶rubidium (an analogue of potassium) was determined on peripheral lymphocytes isolated form 20 normotensive obese subjects and 20 normal weight subjects. No difference in the total uptake of ⁸⁶Rb or in the Na,K-ATPase-dependent uptake was observed in either group. Furthermore, no correlation between the body mass index (BMI) and the Na,K-ATPase-dependent ⁸⁶Rb uptake was observed. However, the Na,K-ATPase mediated ⁸⁶Rb uptake was always positively correlated with basal blood insulin levels and the insulin sensitivity index. It may be concluded that no lymphocyte dysfunction of Na,K-ATPase was present in our obese patients and that its activity is controlled by insulin in both normal-weight and obese subjects.