Moreover, our in vivo results also showed functional rescue of mutant CFTR by ouabain in CF mice and the value corresponds to ∼8.1% of the secretory response of littermate WT control mice and without affecting the mice body weight (control group: starting, 26.36 ± 2.49 g; after 48 h, 26.53 ± 2.63 g, P > 0.2; ouabain treated group: starting, 26.98 ± 2.39 g; after 48 h 27.29 ± 2.33 g, P > 0.2). This evidence concerns the gene CFTR and cystic fibrosis.