Factors contributing to erythrocyte lithium-sodium countertransport activity in lithium-treated bipolar patients

Clinical and biochemical factors related to the activity of the erythrocyte lithium-sodium countertransport (LSC) system were investigated during lithium prophylaxis in 27 patients (13 male, 14 female) with bipolar affective illness. No relationship was found between erythrocyte LSC and such factors as age, gender, duration of lithium prophylaxis, quality of prophylactic lithium response, and family history of affective illness. There was a significant negative correlation between the activity of LSC and the magnitude of the erythrocyte lithium ratio both in whole group and in female patients. In seven patients with concomitant hypertension, the relationship between high activity of LSC and hypertension was not demonstrated. The levels of total cholesterol, HDL cholesterol, triglycerides, and potassium related neither to LSC activity nor to hypertension. Erythrocyte LSC in patients with lower TSH levels were significantly reduced compared to patients with higher TSH. The values of TSH were negatively correlated with T4 but not with T3. Concentrations of T3 were positively correlated with plasma total cholesterol levels. These results are discussed in the view of recent findings on erythrocyte LSC.