Altered erythrocyte Na+ + K+ pump in adolescent obesity

The number of $\text{Na}\text{K}$ pump units and the cation transport activity of the pump were measured in erythrocytes from two etiologically different groups of obese adolescents and a group of normal controls. There was a significant reduction in the number of pump units, as measured by saturation ouabain binding, in erythrocytes from adolescents with idiopathic, early onset obesity. Individuals whose obesity developed subsequent to the appearance of a variety of hypothalamic lesions showed no reduction in the red cell complement of $\text{Na}\text{K}$ pump when compared to controls and the cation transport activity of their cells was higher than both the controls and the subjects with idiopathic obesity. These results support data obtained in adults that reduced red cell $\text{Na}\text{K}$ pump levels are seen in a group of individuals with idiopathic obesity. They further suggest that such reductions are not likely to be secondary to the obese state per se.