Fig. 6.

Inhibition of CLA-induced unidirectional ²²Na⁺ (○) and ⁸⁶Rb⁺ (•) uptake by 5-(N-ethyl-N-isopropyl)-amiloride (EIPA) in nulled isotonic medium. Cells were preincubated in ouabain (1 mM)-containing nulled isotonic media + 500 nM CLA for 35 min. At time 0 cells were placed in isotope-containing nulled isotonic media and sampled over a 5-min interval to measure ²²Na⁺ (○) and ⁸⁶Rb⁺ (•) unidirectional uptake rates. The half-maximal inhibitory concentration (IC₅₀) for EIPA was 1.0 μM for ²²Na⁺ and 1.5 μM for ⁸⁶Rb⁺. Similar results were obtained in 3 experiments.