Figure 7.

Patients with CF (ΔF508/ΔF508) have reduced urine [HCO₃⁻] and a markedly reduced ability to excrete an oral HCO₃⁻ load. (A and B) Baseline urine pH and [HCO₃⁻] in adult patients with CF (n=9) and healthy controls (n=10–11). Note the decreased urine [HCO₃⁻] in patients with CF, t test. *P<0.05. (C, D, and F) Urine pH, urine [HCO₃⁻], and cumulated urinary HCO₃⁻ excretion as response to a NaHCO₃ drinking test (0.94 mmol NaHCO₃/kg body wt) in fasting patients with CF (red, n=9), healthy controls (blue, n=11), and a water drinking test in one fasting patient with CF (bright blue) and fasting healthy controls (black, n=5). Note the greatly reduced urinary [HCO₃⁻] and HCO₃⁻ excretion in patients with CF as compared with healthy controls. *P<0.05, **P<0.01 difference between healthy controls and patients with CF subjected to the oral NaHCO₃ challenge, two-way ANOVA with Bonferroni multiple comparisons test. (E) Area under the curve (AUC) of urinary [HCO₃⁻] in controls (n=11) and patients with CF (n=9). **P<0.01, t test.