Volume 131, Issue 2, Pages 589-605 (August 2006) The Essential Role of Insulin-Like Growth Factor-1 in the Intestinal Tropic Effects of Glucagon-Like Peptide-2 in Mice  Philip E. Dubé, Catherine L. Forse, Jasmine Bahrami, Patricia L. Brubaker  Gastroenterology  Volume 131, Issue 2, Pages 589-605 (August 2006) DOI: 10.1053/j.gastro.2006.05.055 Copyright © 2006 American Gastroenterological Association Institute Terms and Conditions

Figure 1 Characterization of GLP-2 responses in FRIC cultures. (A) RT-PCR for GLP-2R mRNA transcripts in FRIC cultures and adult rat jejunum (top) and IGF-1 mRNA transcripts in FRIC cultures (bottom); + and −RT indicate the inclusion or omission of reverse transcription, respectively. (B) cAMP production by FRIC cultures treated for 30 minutes with 10 μmol/L 3-isobutyl-1-methylxanthine in the absence (control) or presence of h(Gly2)GLP-2 or forskolin. *P < .05 vs control. (C) Relative real-time RT-PCR quantification of IGF-1 mRNA transcripts in FRIC cultures treated for 8 hours in the absence (control) or presence of 10 nmol/L h(Gly2)GLP-2. Expression was normalized for 18S RNA expression. *P < .05 vs control. (D and E) IGF-1 content of (D) medium and (E) cells from FRIC cultures treated for 2 hours in the absence (control) or presence of h(Gly2)GLP-2. **P < .01 vs control; §§P < .01, §§§P < .001 vs 0.1 nmol/L h(Gly2)GLP-2. (F) IGF-1 medium content from FRIC cultures treated for 2 hours with either normal rabbit serum (NRS; control) or GLP-2 immunoneutralizing antibody (GLP2-Ab). *P < .05 vs normal rabbit serum. Gastroenterology 2006 131, 589-605DOI: (10.1053/j.gastro.2006.05.055) Copyright © 2006 American Gastroenterological Association Institute Terms and Conditions

Figure 2 Preliminary in vivo studies in mice treated with vehicle (saline) or 1.6 μg h(Gly2)GLP-2 (GLP-2) every 12 hours for 10 days (n = 6). (A) Mean small intestinal wet weights. (B) Relative levels of ileal IGF-1 and IGF-2 mRNA transcripts, as determined by semiquantitative RT-PCR and normalized for 18S RNA. (C) Relative levels of ileal Msi-1 mRNA transcripts as determined by semiquantitative RT-PCR and normalized for 18S RNA and of jejunal Msi-1 protein as determined by Western blot and normalized for actin. *P < .05, ***P < .001 vs saline-treated controls. (D) Msi-1 labeling indices in proximal jejunal crypt epithelium. Mean values indicate incidence of positive Msi-1 staining at each cell position in the crypt, where the cell at the crypt base was designated position 1. *P < .05, **P < .01 vs saline control at each position. Representative photographs of immunohistochemical staining for Msi-1 (arrowheads) in jejunal crypts from saline- and GLP-2–treated mice are shown. Bars = 20 μm. Gastroenterology 2006 131, 589-605DOI: (10.1053/j.gastro.2006.05.055) Copyright © 2006 American Gastroenterological Association Institute Terms and Conditions

Figure 3 (A) Representative photograph of saline-treated female 8-week-old Igf1+/+ and Igf1−/− littermates and their gastrointestinal tracts. (B) Relative real-time RT-PCR quantification of IGF-1, GLP-2R, and proglucagon mRNA transcripts from distal jejunum of Igf1+/+ and Igf1−/− mice treated with vehicle (saline) or .1 μg/g h(Gly2)GLP-2 (GLP-2 low) every 24 hours for 10 days. ***P < .001 combined Igf1−/− vs combined Igf1+/+. (C) Small and large intestinal wet weights of Igf1+/+, Igf1+/−, and Igf1−/− mice treated with vehicle (saline), .1 μg/g h(Gly2)GLP-2 (GLP-2 low), or 1.0 μg/g h(Gly2)GLP-2 (GLP-2 high) every 24 hours for 10 days, or with vehicle (saline) or 2 μg/g LR3IGF-1 every 12 hours for 10 days, or 8 μg/g R-Spondin1 every 24 hours for 3 days. Upper panels show whole organ wet weight, while lower panels show organ wet weight normalized for body weight. *P < .05, **P < .01, ***P < .001 vs respective saline controls; n values are indicated in parentheses. Gastroenterology 2006 131, 589-605DOI: (10.1053/j.gastro.2006.05.055) Copyright © 2006 American Gastroenterological Association Institute Terms and Conditions

Figure 4 Mean crypt depths and villus heights of intestinal segments from Igf1+/+, Igf1+/−, and Igf1−/− mice as described in Figure 3. *P < .05, **P < .01, ***P < .001 vs respective saline controls. Representative photomicrographs of distal jejunum from Igf1+/+ and Igf1−/− mice treated with saline or GLP-2 low are shown at the bottom. Gastroenterology 2006 131, 589-605DOI: (10.1053/j.gastro.2006.05.055) Copyright © 2006 American Gastroenterological Association Institute Terms and Conditions

Figure 5 Proliferative indices as determined from Ki-67 labeling in crypt epithelium from Igf1+/+, Igf1+/−, and Igf1−/− mice as described in Figure 3. Mean values indicate the incidence of positive Ki-67 staining at each cell position in the crypt, where the cell at the crypt base was designated position 1. *P < .05, **P < .01, ***P < .001 vs saline control at each position. Gastroenterology 2006 131, 589-605DOI: (10.1053/j.gastro.2006.05.055) Copyright © 2006 American Gastroenterological Association Institute Terms and Conditions

Figure 6 (A) Representative photograph of saline-treated female 8-week-old Igf2+ and Igf2−P littermates and their gastrointestinal tracts. (B) Relative real-time RT-PCR quantification of IGF-2 mRNA transcripts from distal jejunum of Igf2+ and Igf2−P mice treated with vehicle (saline) or .1 μg/g h(Gly2)GLP-2 (GLP-2 low) every 24 hours for 10 days. **P < .01 combined Igf2−P vs combined Igf2+. (C) Small and large intestinal wet weights of Igf2+ and Igf2−P mice treated with vehicle (saline), or .1 μg/g h(Gly2)GLP-2 (GLP-2 low) every 24 hours for 10 days, or with vehicle (saline) or 2 μg/g LR3IGF-1 every 12 hours for 10 days. Upper panels show whole organ wet weight, while lower panels show organ wet weight normalized for body weight. *P < .05, ***P < .001 vs respective saline controls, †P < .05 for effect of h(Gly2)GLP-2 in Igf2−P mice vs effect in Igf2+ mice; n values are indicated in parentheses. Gastroenterology 2006 131, 589-605DOI: (10.1053/j.gastro.2006.05.055) Copyright © 2006 American Gastroenterological Association Institute Terms and Conditions

Figure 7 Morphometric analyses of intestinal segments from Igf2+ and Igf2−P mice as described in Figure 6. (A) Mean crypt depths and villus heights. *P < .05 and **P < .01 vs respective saline controls. (B) Mean mucosal cross-sectional area from distal jejunum. *P < .05 vs saline control; †P < .05 for effect of h(Gly2)GLP-2 in Igf2−P mice vs effect in Igf2+ mice. Gastroenterology 2006 131, 589-605DOI: (10.1053/j.gastro.2006.05.055) Copyright © 2006 American Gastroenterological Association Institute Terms and Conditions

Figure 8 Proliferative indices as determined from Ki-67 labeling in crypt epithelium from Igf2+ and Igf2−P mice as described in Figure 6. Mean values indicate incidence of positive Ki-67 staining at each cell position in the crypt, where the cell at the crypt base was designated position 1. *P < .05, **P < .01 vs saline control values at each position. Gastroenterology 2006 131, 589-605DOI: (10.1053/j.gastro.2006.05.055) Copyright © 2006 American Gastroenterological Association Institute Terms and Conditions