Familial aggregation of red blood cell cation transport systems in Japanese families.

The rate of lithium, sodium, and potassium transport in red blood cells is thought to be associated with essential hypertension. In order to investigate the contribution of genetic and environmental factors to cation transport, their correlation was analyzed in 60 parent-offspring pairs and 17 husband-wife pairs in Toyama City, Japan. Lithium-sodium countertransport and sodium-potassium cotransport rates were significantly correlated in parent-offspring pairs (r = 0.52, p less than 0.01 and r = 0.46, p less than 0.01, respectively) but not in husband-wife pairs. Sodium pump rates were significantly correlated in both pairs (r = 0.48, p less than 0.01 in parent-offspring pairs, r = 0.46, p less than 0.05 in husband-wife pairs). Therefore, lithium-sodium countertransport and sodium-potassium cotransport were found to have a substantial genetic component and the sodium pump to have a substantial environmental component. Sodium pump rates were significantly correlated with sodium/creatinine (r = 0.21, p less than 0.05) and sodium/potassium (r = 0.32, p less than 0.01) in casual urine.