Lithium transport in red cells of patients with affective disorders.

Variation in red cell Li+ transport as mediated by the Li+-Na+ exchange pathway (Li+-Na+ counterflow) appears to cause wide variation between psychiatric patients in the Li+ ratio (erythrocyte/plasma) in vivo during Li+ treatment. We obtained significant correlations between Li+ ratios determined in vivo and several measures of Li+ transport as mediated by Li+-Na+ exchange. Patients with bipolar illness had significantly lower rates of Li+ transport as mediated by this pathway than did normal subjects.