Erythrocyte sodium-lithium countertransport in Chinese: its relationship to family history of hypertension.

Rates of sodium (Na+)-stimulated lithium (Li+) efflux (Na(+)-Li+ countertransport) and ouabain-sensitive Na+ efflux (Na+ pump) were determined in erythrocytes of Chinese normotensive and hypertensive subjects. Near-maximal rate of Na(+)-Li+ countertransport was found to be significantly higher in hypertensive than normotensive subjects. No significant difference was observed for the rate of Na+ pump between them. A second series of study involved normotensive subjects without and with hypertensive parent(s) (group A and B, respectively) and hypertensive subjects (group C). We found that the rate of Na(+)-Li+ countertransport in group A was significantly lower than that of group B and C, while no difference existed between group B and C. No significant difference was observed for the rate of Na+ pump among the three groups. Our results suggested that Na(+)-Li+ countertransport activity could be a genetic marker for essential hypertension in Chinese, similar to that as proposed in Caucasians.