LITHIUM TRANSPORT PATHWAYS IN HUMAN, CHICKEN AND EEL ERYTHROCYTES

The contribution of four transport pathways to Li+ influx in human, ch icken and eel erythrocytes was studied. All pathways were measured sim ultaneously in each kind of blood sample to avoid possible temporal va riations in transport parameters. We found that: 1) Li+ influx via Na-K+ pump increased 2-3 fold in the order human < eel < chicken; 2) by the countertransport exchange system lithium influx increases its vari ance between 15 % and 35 % when saline medium is replaced by choline C l; 3) the anion exchange system (band 3 protein) shows very little int erindividual variability on the lithium influx; 4) the lithium leak pa thway, for human and eel red blood cells, is the major contribution,wh ereas it is negligible for chicken erythrocytes. It is concluded that a similar transport system exists in the red cell membranes of the thr ee species which can transport lithium. However, the exchange system d oes not exhibit identical transport characteristics in the three speci es and shows a marked inter- and intra-species variability in maximum transport capacity and some differences in susceptibility towards the inhibitors. (C) 1995 Academic Press, Inc.