Elevation of red cell sodium-lithium countertransport in hyperlipidemias.

Red cell Na-Li countertransport was measured in 78 normal subjects, 64 patients with essential hypertension, and 67 patients with hyperlipidemias. Both hypertensive and hyperlipidemic patients had elevated Na-Li countertransport compared to normal controls (p less than 0.001). Subjects with hyperlipidemia and hypertension had higher countertransport (p less than 0.02) than patients with only hyperlipidemia. Normotensive hyperlipidemic subjects had higher countertransport than normotensive and normolipidemic controls (p less than 0.02). This suggest that hypertension and high plasma lipids can influence independently the Na-Li countertransport. In another group of 52 normotensive subjects, Na-Li countertransport was positively correlated with serum total and free (unesterified) cholesterol, phospholipids and triglycerides. No correlations were found with HDL-cholesterol or HDL-phospholipids. A very high positive correlation was found between Na-Li countertransport and plasma acetylcholinesterase (p less than 0.005). These findings suggest that plasma lipids, probably through membrane lipids, can affect the maximal rate of the Na-Li exchange in red cells. The relationship between plasma or membrane lipids and cation transport should be further studied in erythrocytes and other cells.

Lithium-sodium countertransport in erythrocytes of normal and hypertensive subjects. Relationship with age and plasma renin activity.

Lii-Nao countertransport was measured in red blood cells of 58 normotensive subjects (27 females and 31 males), 60 patients with essential hypertension (26 females and 34 males), and in 28 with secondary hypertension (19 females and 9 males). The mean values (+/- SEM) expressed as mmol Li (1 red cells X hr)-1 were 0.18 +/- 0.02 (females) and 0.20 +/- 0.01 (males) in the control group, 0.34 +/- 0.04 (females) and 0.39 +/- 0.03 (males) in essential hypertension, 0.16 +/- 0.03 (females) and 0.19 +/- 0.02 (males) in secondary hypertension. The mean value of Lii-Nao countertransport obtained in essential hypertension was statistically different from those obtained in both normals (p less than 0.001) and patients with secondary hypertension (p less than 0.001). A negative correlation was found between age and Lii-Nao countertransport in normotensive males (r = - 0.648; p less than 0.001) but neither in normal females nor in patients with essential hypertension. A positive correlation (r = + 0.425; p less than 0.05) was found between plasma renin activity after intravenous furosemide and Lii-Nao countertransport in essential hypertension. These findings support the hypothesis of a characteristic cation transport across the red blood cell membrane of patient with essential hypertension which might be correlated with the plasma renin activity.