Ouabain-resistant phenomenon and changes of transmembrane ion transport in essential hypertensives with a family history of hypertension

摘要

Objective: To investigate the role of heredity in the ouabain-resistant phenomenon and the rela tionship between ouabain-resistance and transmembrane ion transport in essential hypertensives. Methods:A total of 52 essential hypertensives were investigated. of the patients, 23 were with a family history of hyper tension (FH+ group) and 29 were without (FH- group). Other 25 normotensives were employed to serve as the controls (control group). The percentage of 125I-digoxin binding to red blood cells (RBC-D% ) and plasma endogenous digoxin-like substance (EDLS) were measured with radioimmunoassay, 45Ca2+ influx in ATP-de pleted red cells by liquid scintillation counting. The rate constant of ouabain-sensitive sodium efflux (°Kos, h-1) was analyzed as half the increase in erythrocyte Na+ concentration during incubation with ouabain for 2 h. The maximal rate (Vmax) of red cell Na+/H+ exchange was determined as the influx promoted by an out ward H+ gradient then calculated. Results:The ouabain-sensitive Na+ efflux and RBC-D% were significantly lower but the levels of plasma EDLS and 45Ca2+ influx significantly higher in both FH+ and FH groups than in the control group. The plasma EDLS and ouabain-sensitive Na+ efflux were significantly higher but Ca2+ innux lower in FH+ group than in FH- group. Positive correlation was found between RBc-D% and ca2+ in flux in FH+ group. Conclusion: Ouabain-resistant phenomenon is related to the heredity of hypertension.The decrease in affinity of EDLS for membrane affects the transmembrane ion transport, which may partici pate in the pathogenesis of salt-sensitive hypertension.