Functionally Abnormal Na⁺-K⁺ Pump in Erythrocytes of a Morbidly Obese Patient

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Abstract

The Na+-K+ pump in the erythrocytes of a mordibly obese patient shows a unique constellation of functional abnormalities. The number of pump units, measured by [3H]ouabain binding to intact cells, as well as the enzymatic activity of the (Na+-K+)-dependent ATPase in erythrocyte membranes were found to be markedly increased compared with control cells (18-fold and 14-fold, respectively). There was a concomitant fivefold increase in the rate of pump-mediated uptake of 86Rubidium (a K analogue); this was balanced by an increased rate of 86Rb efflux. In striking contrast to normal cells, however, a major portion of this efflux (80%) was inhibited by ouabain, and thus appeared to be mediated by the Na+-K+ pump.

Authors

Mario Deluise, Jeffrey S. Flier