Figure 4.

Increased parietal cell activation and acid secretion in TFF2-deficient mice. (a) Increased basal gastric acid secretion in fed TFF2-deficient mice. Basal gastric acid output was calculated in the resting state of fed wild-type and TFF2-deficient mice and expressed as μEquivalent of H⁺. Results are expressed as mean acid output ± SEM and represent data from analysis of eight wild-type mice and eight TFF2-deficient mice. (P < 0.05). (b) Increased stimulated gastric acid secretion in TFF2-deficient mice. Stimulated gastric acid output was calculated in wild-type and TFF2-deficient mice after administration of bethanechol (2.5 mg/kg intraperitoneally) and expressed as μEquivalent of H⁺. Results are expressed as mean acid output ± SEM and represent data from analysis of eight wild-type mice and eight TFF2-deficient mice. (P < 0.04). (c) Parietal cell activation. Random low-powered electron micrographs were obtained (×3,000). Both activated and inactivated parietal cells are identified by their unique ultrastructure. Activated parietal cells are defined as cells having an expansion of their secretory canaliculi. Inactive parietal cell (left panel). Activated parietal cell (right panel). (d) Increased parietal cell activation in fed TFF2-deficient mice compared with wild-type mice under resting conditions. Results are expressed number of activated parietal cells as a percentage of total parietal cells counted ± SE of four mice. (P < 0.02). (e) No change in HB-EGF protein expression. Western blot analysis of stomach protein (50 μg total protein per lane) shows no difference in expression of HB-EGF protein in TFF2-deficient (–/–) compared with wild-type mice (+/+). Purified human HB-EGF was used as a positive control (not shown). M, size marker; MW, molecular weight.