Wheat‐ghretropins: novel ghrelin‐releasing peptides derived from wheat protein

Ghrelin is an endogenous orexigenic hormone mainly produced by stomach cells and is reported to influence appetite, gastrointestinal motility and growth hormone secretion. We observed that enzymatic digest of wheat gluten stimulated ghrelin secretion from mouse ghrelinoma 3-1, a ghrelin-releasing cell line. Further on, we characterized the ghrelin-releasing peptides present in the digest by comprehensive peptide analysis using liquid chromatography-mass spectrometry and structure-activity relationship. Among the candidate peptides, we found that SQQQQPVLPQQPSF, LSVTSPQQVSY and YPTSL stimulated ghrelin release. We then named them wheat-ghretropin A, B and C, respectively. In addition, we observed that wheat-ghretropin A increased plasma ghrelin concentration and food intake in mice after oral administration. Thus, we demonstrated that wheat-ghretropin stimulates ghrelin release both in vitro and in vivo. To the best of our knowledge, this is the first report of a wheat-derived exogenous bioactive peptide that stimulates ghrelin secretion

A Novel Method to Detect 3D Mandibular Changes Related to Soft-Diet Feeding

Craniofacial morphology varies among individuals, which is regulated by the interaction between genes and the environment. Soft-diet feeding is a widely-used experimental model for studying the association between the skeletal morphology and muscle-related loading on the bone. Traditionally, these studies have been based on linear and angular measurements provided on two-dimensional (2D) radiographs in the lateral view. However, 2D observation is based on simplification of the anatomical structures and cannot detect three-dimensional (3D) changes in detail. In this study, we newly developed a modified surface-based analysis with micro-3D computed tomography (CT) to examine and detect the 3D changes in the mandible associated with soft-diet feeding. Mice at 3 weeks of age were fed a powdered soft-diet (SD) or hard-diet (HD) of regular rodent pellets until 9 weeks of age. Micro-CT images were taken at age 9 weeks to reconstruct the anatomical architecture images. A computer-generated averaged mandible was superimposed to directly visualize the morphological phenotypes. Gross observation revealed the apparent changes at the posterior body of the mandible, the angular process and the condyle between HD and SD mice. Significant differences in the mapping indicated the regions of significant displacement in the SD mice over the averaged 3D image of the HD mice. This map revealed that vertical displacement was most evident in 3D changes. We also noted a combination of vertical, transverse and anteroposterior directions of displacement in the condylar growth, resulting in complicated shape changes in the whole condylar process in SD mice. In contrast, transverse displacement was more significant in the coronoid process. The map analysis further showed the significant outward displacement of the inner surface of the alveolar process, which consequently resulted in thinning of the alveolar process