An inverse relationship between HDL-c plasmatic levels and Li+ flux (Na+-Li+ exchange mediated) has been reported in normotensive individuals with hypertensive ancestors as well as in essential hypertensive subjects. This lipoprotein reaction with plasmatic membrane components induces modifications in membrane transport mechanisms as well as in cellular enzymes. In this paper we present data on Li+ flux (Na+-Li+ exchange mediated) in red blood cells from normotensive individuals without hypertensive ancestors. Kinetic analysis of Li+ efflux as a function of Na+(extracell) concentration was carried out. Vmax and Km values were determined. HDL-c plasmatic levels were also determined. Vmax showed a significant inverse correlation with HDL-c levels. No significant correlation of Km values with HDL-c levels was observed. The data presented support previous data showing that variable Vmax is sensitive to cellular environmental factors. Otherwise the Km variable not influenced by these factors is sensitive to hereditary influences.