Erythrocyte Sodium-Potassium-ATPase and Obesity

To the Editor: The conclusions of the paper by Mir et al. on erythrocyte sodium-potassium-ATPase and sodium transport in obesity (November 19 issue)¹ differ from ours.² Their conclusions are based on two assays — sodium efflux from red cells and sodium-potassium-ATPase activity in erythrocyte-derived vesicles — neither of which was performed in our initial study.² Because Mir et al. did not in fact attempt to reproduce our study, we believe that caution in the interpretation of apparently discordant results is warranted. These authors cite a coefficient of variance of less than 8 per cent in their measurements of vesicle ATPase,.