Pancreatic acinar cell dysfunction in CFTR−/− mice is associated with impairments in luminal pH and endocytosis  Steven D. Freedman, Horst F. Kern, George A. Scheele  Gastroenterology  Volume 121, Issue 4, Pages 950-957 (October 2001) DOI: 10.1053/gast.2001.27992 Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig. 1 Morphologic assessment of the pancreas. Representative electron micrographs of the pancreas from WT mice (A), heterozygous mice (cftr+/−; B), and cftr−/− mice (C–F) are shown. In E and F, the pancreatic lobules from cftr−/− mice prestimulated with CCK were incubated in KHB at pH 8.0. L indicates lumen, and the bars indicate 1 μm. Gastroenterology 2001 121, 950-957DOI: (10.1053/gast.2001.27992) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig. 2 Analysis of CCK-stimulated amylase secretion. Amylase secretion was measured from lobules obtained from WT, cftr+/− (heterozygote [HT]), and cftr−/− (CF) mice after a 60-minute incubation in the absence or presence of 0.5 nmol/L CCK-8. Results are expressed as the means ± SEM from at least 3 separate experiments and are presented as the fold stimulation over basal secretion levels. No statistically significant differences were present between the 3 animal groups. Gastroenterology 2001 121, 950-957DOI: (10.1053/gast.2001.27992) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig. 3 Analysis of HRP uptake as a function of pH. Using the 2-step protocol, HRP uptake was analyzed as a function of pH of the medium over a 30-minute incubation at 37°C in pancreatic lobules from WT, cftr+/− (HT), and cftr−/− (CF) mice. Results are expressed as mean HRP uptake (nanogram/milligram total protein) ± SEM from at least 3 separate experiments. HRP uptake was significantly reduced in cftr−/− mice compared with WT mice at pH values of 6.5 and 7.0 (P < 0.01) and at 7.5 and 8.0 (P < 0.05). The difference between heterozygous and WT mice was not statistically significant. Gastroenterology 2001 121, 950-957DOI: (10.1053/gast.2001.27992) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig. 4 Effect of PI-PLC on HRP uptake in lobules from cftr−/− mice. Using the same protocol described in Figure 3, pancreatic lobules from cftr−/− mice were incubated in KHB medium at pH 6.0 alone, medium at pH 6.0 with PI-PLC, or in medium at pH 8.3. Results are expressed as mean HRP uptake (nanogram/milligram of total protein) ± SEM from at least 3 separate experiments. The values at pH 6.0 alone were statistically different (P < 0.005) compared with pH 6 + PI-PLC or pH 8.3. Gastroenterology 2001 121, 950-957DOI: (10.1053/gast.2001.27992) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig. 5 Analysis of GP2 release from pancreatic lobules from cftr−/− mice. Using a similar protocol to that described in Figure 4, the % GP2 release into the medium was measured by western blot quantitation. Results are expressed as the means ± SEM from 4 separate experiments. Only the values at pH 6.0 compared with those at pH 7.4 were statistically different (P < 0.001). Gastroenterology 2001 121, 950-957DOI: (10.1053/gast.2001.27992) Copyright © 2001 American Gastroenterological Association Terms and Conditions