Essential hypertension and membrane lithium transport in depressed patients.

Na+-Li+ countertransport activity in erythrocytes has previously been reported to be decreased in certain patients with mood disorders, but increased in essential hypertensives and possibly their first-degree relatives. The present investigation examines specific parameters of Na+-Li+ countertransport in relation to both affective disorder and essential hypertension. Depressed patients having a personal or family history of essential hypertension had significantly higher Vmax and fractional lithium release values than did other patients or control subjects. Values of K 1/2 did not differ among the groups. Essential hypertension in experimental subjects or their families may complicate attempts to study human erythrocyte (RBC) lithium transport in depressed patients.