Volume 119, Issue 3, Pages 756-765 (September 2000) Glycine-extended gastrin synergizes with gastrin 17 to stimulate acid secretion in gastrin-deficient mice  Duan Chen, C.–M. Zhao, Graham J. Dockray, Andrea Varro, Alfred Van Hoek, Natalie F. Sinclair, Timothy C. Wang, Theodore J. Koh  Gastroenterology  Volume 119, Issue 3, Pages 756-765 (September 2000) DOI: 10.1053/gast.2000.16480 Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 1 G17-Gly augments G-17–induced acid secretion in gastrin-deficient mice. (A) Sixty gastrin-deficient mice received infusions of saline, G17-Gly, G-17, or both G-17 and G17-Gly for 1, 6, or 14 days. Acid secretion over 4 hours was determined by the the pyloric ligation method and expressed as nEq H+ (*P < 0.01 compared with saline and G-17 infusions). (B) Twenty-four gastrin-deficient mice received a 14-day infusion of 1, 2, 5, or 10 nmol · kg−1 · h−1 of G-17. Acid secretion over 4 hours was determined by the pyloric ligation method and expressed as nEq H+. (C) Eighteen gastrin-deficient mice received a 14-day infusion of 1, 2, or 10 nmol · kg−1 · h−1 of both G-17 and G17-Gly. Acid secretion over 4 hours was determined by the pyloric ligation method and expressed as nEq H+ (*P < 0.01 compared with infusion of G-17 alone). Gastroenterology 2000 119, 756-765DOI: (10.1053/gast.2000.16480) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 2 G17-Gly has no effect on fundic proliferation. BrdU incorporation was detected by immunoperoxidase staining of 10 well-oriented glands per slide from gastrin-deficient mice receiving 2-week infusions of saline, G17-Gly, G-17, or both G-17 and G17-Gly. The BrdU labeling index (LI%) was determined by counting the number of immunopositive stained cells per gland divided by the total number of cells per gland. *P < 0.01 compared with saline infusion. Gastroenterology 2000 119, 756-765DOI: (10.1053/gast.2000.16480) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 3 G17-Gly has no effect on parietal cell number. Parietal cell number was determined by H&E and immunostaining the stomachs of gastrin-deficient mice receiving 2-week infusions of saline, G17-Gly, G-17, or both G-17 and G17-Gly, with an antibody to H+,K+-ATPase. Parietal cell number is expressed as the number of parietal cells from 10 well-oriented fundic glands per slide divided by 10 (*P < 0.01 compared with saline infusion). Gastroenterology 2000 119, 756-765DOI: (10.1053/gast.2000.16480) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 4 G17-Gly has no effect on ECL cell number. ECL cell number was determined by immunostaining the stomachs of gastrin-deficient mice receiving a 2-week infusion of saline, G17-Gly, G-17, or both G-17 and G17-Gly with an antibody to either (A) histamine or (B) VMAT-2. ECL cell number is expressed as the total number of ECL cells in 10 well-oriented fundic glands per slide divided by 10. Gastroenterology 2000 119, 756-765DOI: (10.1053/gast.2000.16480) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 5 Infusion of gastrin has no effect on H+,K+-ATPase expression. Immunohistochemical staining with an antibody specific for H+,K+-ATPase was performed on the stomachs of gastrin-deficient mice receiving a 2-week infusion of (A) G-17 and G17-Gly or (B) saline. There is a significantly greater number of immunopositive cells in A but no discernible difference in intensity of immunostaining between A and B. (C) Fifty milligrams of fundic protein from gastrin-deficient mice receiving 2 nmol · kg−1 · h−1 of either G-17 or both G-17 and G17-Gly were loaded onto a 10%–20% Tricine gel for Western blot analysis using an antibody to the β subunit of H+,K+-ATPase. Gastroenterology 2000 119, 756-765DOI: (10.1053/gast.2000.16480) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 5 Infusion of gastrin has no effect on H+,K+-ATPase expression. Immunohistochemical staining with an antibody specific for H+,K+-ATPase was performed on the stomachs of gastrin-deficient mice receiving a 2-week infusion of (A) G-17 and G17-Gly or (B) saline. There is a significantly greater number of immunopositive cells in A but no discernible difference in intensity of immunostaining between A and B. (C) Fifty milligrams of fundic protein from gastrin-deficient mice receiving 2 nmol · kg−1 · h−1 of either G-17 or both G-17 and G17-Gly were loaded onto a 10%–20% Tricine gel for Western blot analysis using an antibody to the β subunit of H+,K+-ATPase. Gastroenterology 2000 119, 756-765DOI: (10.1053/gast.2000.16480) Copyright © 2000 American Gastroenterological Association Terms and Conditions

Fig. 6 Coinfusion of G17-Gly and G-17 results in an increased number of activated parietal cells compared with infusion of G-17 alone. Electron microscopy was performed to examine for the presence of (A) resting parietal cells and (B) activated parietal cells in gastrin-deficient mice receiving a 2-week infusion of saline, G17-Gly, G-17, or both G-17 and G17-Gly. (C) A total 100 parietal cells from each mouse were analyzed, and the percentage of activated parietal cells was determined. (D) These parietal cells were also examined for the presence of lipofuscin bodies (arrows) and vacuolar canaliculi (*), and the (E) percentage of cell density occupied by vacuolar canaliculi and (F) percentage of cell density occupied by lipofuscin bodies were determined (*P < 0.01 compared with saline infusion). Gastroenterology 2000 119, 756-765DOI: (10.1053/gast.2000.16480) Copyright © 2000 American Gastroenterological Association Terms and Conditions