K-Cl cotransport activity of WT and SAD red cells was measured in isotonic medium (ISO), hypotonic medium (Hypo), isotonic medium containing 1 μM staurosporine (Stauro), and isotonic medium with added 500 mM urea (Urea). Values are means ± SEM for (n) independent experiments with blood pooled from 2–4 mice of indicated genotype. ISO WT red cells (n=5) included WTC57 (n=2), WTKcnn4 (n=2) and WTSAD (n=1). WT red cells in stimulated conditions were (for HYPO, n=10) 1 WTC57 + 9 WTKcnn4; (for Stauro, n=8) 1 WTC57 + 7 WTKcnn4; and (for Urea, n=9) 1 WTC57, 1 WTSAD, and 7 WTKcnn4. WT and SAD samples were compared for each condition by Mann-Whitney non-paired test.