Figure 3. Na⁺ transport kinetics of NHE1 in mildly hyperosmotic medium.

The Michaelis-Menten Na⁺ transport kinetics were determined for NHE1 in atRBCs following complete activation in mildly hyperosmotic (1.2×IR) medium alone (closed triangles), hyperosmotic (1.2×IR) medium with 500 nM CLA (open triangles), or CLA treatment alone in IR (squares). Data for resting atRBCs in isosmotic medium are shown for comparison (small squares, dashed curve). The data are fit by regression to a simple hyperbola, and the corresponding kinetic constants are reported in Table 2. The Na⁺ transport affinity is not significantly different across the three conditions. However, the maximal transport rate J_max is significantly increased in hyperosmotic media together with CLA treatment, relative to either treatment alone (p<0.05). (data are compiled from n≥3 independent experiments; means ± SE).