THE EFFECT OF LITHIUM TREATMENT ON ERYTHROCYTE MEMBRANE ATPase ACTIVITIES AND ERYTHROCYTE ION CONTENT

Abstract

ATPase activities were studied in erythrocyte membranes prepared from blood of patients suffering from affective disorders. Long‐term (9–12 months) administration of lithium led to an increase in the erythrocyte membrane Na/K ATPase activity (54%) when studied on an age and sex matched basis or when the patients were studied before and after treatment. The Mg ATPase activity was also increased (38%) but there was no consistent effect of lithium treatment on Ca stimulated ATPase activity in the membranes. It is suggested that the effect of lithium treatment on Na/K ATPase was due to recovery of the patients rather than an effect of the drug. MgATPase activity increased regardless of clinical condition. Short‐term lithium treatment (2–4 weeks) led to increased Mg ATPase activity (43%). These results suggest that lithium treatment itself causes an increase in Mg ATPase activity and that this effect is not dependent on changes in protein synthesis. Lithium treatment (long‐term) increased the erythrocyte sodium content by 15%. No effect on plasma sodium, magnesium, potassium or erythrocyte magnesium and potassium was observed.