Red cell sodium-potassium adenosine triphosphatase sites and intracellular sodium increased in obese school children.

Principally to ascertain whether mineral metabolism is involved in weight regulation, the 40 most obese of 1,774 children, aged 10-11 years, screened for obesity were compared with 46 age-matched controls. The obese children had more 3H-Ouabain erythrocyte binding sites (p = 0.04), higher intracellular sodium (p = 0.04), and lower plasma sodium (p = 0.002). After exclusion of the non-Scandinavians, the p values were p = 0.02, p = 0.03, and p = 0.03, respectively. Analysis of variance also showed the differences to be more dependent on obesity than on gender or nationality. It is concluded that obese children have more 3H-Ouabain erythrocyte binding sites indicating an increase of the sodium-potassium adenosine triphosphatase activity. The increase of intracellular sodium may increase the risk of future hypertension.