Loss of SNAP23 results in decreased ZG secretion. (A) Body weight of control (Ctrl) and AcKO mice. Three mice per genotype were examined. (B) SNAP23 and phalloidin (apical marker) staining in pancreatic acinar cells. SNAP23 localized to the plasma membrane in the control acinar cells, but the staining disappeared in the AcKO acinar cells. Bar, 20 µm. (C) SNAP23 levels evaluated by Western blotting in the islet-excluded pancreas tissue from control and AcKO mice. GAPDH was used as a loading control. A total of 20 µg protein is loaded in each well. (D) HE staining of the control and AcKO acinar cells. Bar, 50 µm. (E) Electron micrographs of acinar cells from control and AcKO mice without CCK stimulation (left panels) and after CCK stimulation (middle panel: low magnification; right panel: high magnification of the squares in the middle panel). Bars, 5 µm. (F) Quantification of ZG density per cytoplasmic area in ultrathin sections without CCK stimulation and after CCK stimulation. Analysis was performed on 8 control acinar cells and 10 AcKO acinar cells, scored in 2 mice per genotype. (G) Amylase secretion is reduced in AcKO acinar cells. Control and AcKO acinar cells were incubated with CCK, and the amount of secreted amylase was measured. The data are representative of three independent experiments. (H) Sudan III staining of stool smear preparation of control and AcKO mice. Arrows indicate lipid droplets. Bar, 50 µm. (I) Percentage of triglyceride in stools from control and AcKO mice. Three mice per genotype were used to collect stools. Data are mean ± SEM. Significance was calculated by the two-tailed paired Student’s t test. *, P < 0.05; **, P < 0.01; ***, P < 0.001.