Erythrocyte Li-Na countertransport in hypertension: lack of atrial natriuretic peptide effect.

The rate of erythrocyte Li-Na countertransport and cellular Na+ and K+ contents have been determined in normotensive (NT) and hypertensive (HT, essential hypertension) subjects in the presence and absence of atrial natriuretic peptide (ANP). The rate of Li-Na countertransport was significantly higher in erythrocytes of HT subjects, while the Na+ and K+ contents were not different between the NT and HT groups. We found that ANP (10(-9) and 10(-7) M) had no effect on either the rate of Li-Na countertransport or the cellular Na+ and K+ contents. Since ANP does not influence erythrocyte Na pump and Na-K-Cl cotransport, our results suggest that the Na transport systems of human erythrocytes do not respond to ANP and this lack of response in Li-Na countertransport is independent of the status of hypertension. These findings are consistent with the view that the rate of Li-Na countertransport of erythrocytes may serve as a useful genetic marker for essential hypertension in Chinese. However, the erythrocyte transport systems cannot provide further differentiation utilizing ANP response for essential hypertension.