Body weight and fat mass in ΔF508 mutant mice. A–D: Body weight (A and B) and weight gain (C and D) were measured from 4 to 14 weeks of age in male (A and C) and female (B and D) WT, HET, and ΔF508 mice. Data are expressed as mean ± SEM of 7–15 mice per group. *P < 0.05, **P < 0.01, ***P < 0.001 vs. WT. E and F: Fat mass content relative to body weight was assessed by EchoMRI in 11-week-old WT, HET, and ΔF508 male (E) and female (F) mice. Data are mean ± SEM of 9–20 mice per group. **P < 0.01 vs. WT.