Figure 8. Loss of acid secretion (A) and increase in HCO₃⁻ secretion (B) in the gastric mucosa of adult mice (3–6 months).

A, high K⁺ concentrations increase the basal acid secretory rate in gastric mucosa of adult WT mice but, in contrast to the situation in very young mice, cannot rescue acid secretion in adult KCNQ1^−/− mice (n= 11, 5 and 5 for the first three bars and 4, 4 and 3 for the second three bars, n.t.a. indicates no titratable acid). B, in contrast, the hypertrophied gastric mucosa of adult KCNQ1^−/− mice secretes significantly more HCO₃⁻ than the WT mucosae (after inhibition of acid secretion by 10⁻⁵m omeprazole). n= 5. *P < 0.05, ***P < 0.0001.