Meta-analysis of erythrocyte Na,K-ATPase activity in bipolar illness.

Sodium, potassium-activated adenosine triphosphatase (Na,K-ATPase) pump activity has been variously reported to be increased, decreased, or unchanged in bipolar patients. To explore this association we conducted a meta-analysis of the available literature. All papers containing data on erythrocyte Na,K-ATPase activity were reviewed independently by both authors. A meta-analysis of these data was accomplished by standard procedure. We found a significant mood-state-related decrease in Na,K-ATPase activity in both manic and bipolar depressed patients when compared to euthymic bipolar patients, but not when ill patients were compared to normal controls. The overall change can be characterized as small to moderate in magnitude.