Peptide YY Regulates Bone Turnover in Rodents Katherine E. Wortley, Karen Garcia, Haruka Okamoto, Karen Thabet, Keith D. Anderson, Victor Shen, Jim P. Herman, David Valenzuela, George D. Yancopoulos, Matthias H. Tschöp, Andrew Murphy, Mark W. Sleeman  Gastroenterology  Volume 133, Issue 5, Pages 1534-1543 (November 2007) DOI: 10.1053/j.gastro.2007.08.024 Copyright © 2007 AGA Institute Terms and Conditions

Figure 1 Generation of Pyy−/− and Ppy−/− mice. (A) Schematic diagram of the murine wild-type Pyy alleles and the targeting vectors used to generate a null Pyy allele by precise substitution of the lacZ reporter gene and neo selectable marker. (B) Schematic diagram of the murine wild-type Ppy alleles and the targeting vectors used to generate a null Ppy allele by precise substitution of the lacZ reporter gene and neo selectable marker. Gastroenterology 2007 133, 1534-1543DOI: (10.1053/j.gastro.2007.08.024) Copyright © 2007 AGA Institute Terms and Conditions

Figure 2 Immunostaining of Pyy (top panels) and Ppy (bottom panels) in pancreatic islets of WT, Pyy−/−, and Ppy−/− mice. Gastroenterology 2007 133, 1534-1543DOI: (10.1053/j.gastro.2007.08.024) Copyright © 2007 AGA Institute Terms and Conditions

Figure 3 β-galactosidase staining reveals specific reporter gene expression (LacZ reporter, in blue) in pancreatic islet cells and enteroendocrine cells of the ileum and colon. (Top panels) A female Pyy+/− (right), a 14-week-old male Pyy−/− (middle), and a female Pyy+/− mouse (left) (8–16 weeks old). (Bottom panels) Male Ppy−/− mice (16 weeks old). Yellow arrows indicate lacZ-positive cells (bar = 100 μm). d, duct; il, islet of Langerhans; iv, intestinal villi; el, endothelial lining; l, lumen; lp, lamina propria; mm, muscularis mucosae; mg, mucosal gland; gc, goblet cell. Gastroenterology 2007 133, 1534-1543DOI: (10.1053/j.gastro.2007.08.024) Copyright © 2007 AGA Institute Terms and Conditions

Figure 4 Pyy or Ppy deletion does not impair body weight gain or food intake on a standard diet. (A) Body weights of male F2 or N3F2 WT or Pyy−/− mice maintained on standard chow. (B) Cumulative food intake, (C) oxygen consumption, and (D) respiratory quotient in male F2 WT and Pyy−/− mice on standard chow. (E) Body weights and (F) cumulative food intake in male and female F2 WT or Ppy−/− mice maintained on standard chow. Data represent mean ± SEM of n = 11–17 mice/genotype for Pyy and 6–9 mice/genotype for Ppy mice. Bars in B–D and F represent the dark period. Gastroenterology 2007 133, 1534-1543DOI: (10.1053/j.gastro.2007.08.024) Copyright © 2007 AGA Institute Terms and Conditions

Figure 5 Decreased bone mass and bone strength in Pyy−/− mice. Whole body (A) BMD and (B) BMC in 2- and 6-month-old male F2 WT and Pyy−/− mice as measured by PIXI. Histomorphometry analysis of vertebrae from 9-month-old Pyy−/− mice showing (C and D) reduced trabecular bone volume and number and (E and F) a decrease in bone volume over tissue volume (BV/TV) compared with WT littermates. Data represent mean ± SEM of n = 9–16 mice/genotype. Asterisks indicate statistically significant differences between 2 groups (*P < .05, **P < .01). Gastroenterology 2007 133, 1534-1543DOI: (10.1053/j.gastro.2007.08.024) Copyright © 2007 AGA Institute Terms and Conditions

Figure 6 Increased sensitivity to high-fat diet–induced weight gain and estrogen-induced bone loss in Pyy−/− mice. Exposure to a high-fat diet caused (A) greater weight gain in Pyy−/− mice relative to WT littermates and (B) induced greater adiposity in female mice after 17 weeks on the diet. (C and D) Male and female Pyy−/− mice maintained reduced BMD and BMC on a high-fat diet despite greater weight gain. Data represent mean ± SEM of n = 8–18 mice/genotype. (E) Ovariectomy caused a greater loss of BMD in Pyy−/− female mice fed a standard diet compared with WT littermates, whereas (F) body weight remained similar between the 2 genotypes. Total BMD and BMD in the lumbar vertebrae and femur were measured before and 4 weeks after ovariectomy. The percentage loss of BMD relative to the initial value is shown. Body weight data represents weights at 4 weeks postsurgery. Data represent mean ± SEM of n = 4–6 mice/genotype. Asterisks indicate statistically significant differences between 2 groups (*P < .05, **P < .01). Gastroenterology 2007 133, 1534-1543DOI: (10.1053/j.gastro.2007.08.024) Copyright © 2007 AGA Institute Terms and Conditions