Effect of age on red cell membrane sodium-potassium dependent adenosine triphosphatase (Na⁺-K⁺ ATPase) activity in healthy men

Decreased cellular thermogenesis may represent a normal aspect of the aging process. Whereas Na⁺-K⁺ ATPase appears to be involved directly in body metabolism, enzyme activity on the erythrocyte membrane was measured in two groups of healthy ambulatory men aged 28 to 35 and 63 to 100. Red cell membrane Na⁺-K⁺ ATPase was significantly lower in aged men. In a separate series of experiments, each with representation from the two age groups, red cell membrane Na⁺-K⁺ ATPase was also found to be decreased significantly in the aged men. Although mean values were statistically different, one of the elderly men had enzyme activity above that of the mean of the younger men. None of the younger men had enzyme activity below the mean of the older group. Red cell membrane Na⁺-K⁺ ATPase activity may be an indicator of physiological aging.