Immunolocalization of the PP family and its receptors in the gastrointestinal tract of house musk shrew, Suncus murinus.

OBJECTIVES: To investigate the immunolocalization of the pancreatic polypeptide (PP)-fold peptide family, important regulatory factors for food intake, in the gastrointestinal tract of Suncus murinus, and to discuss the relation with the obesity-resistance, visceral fat accumulation-resistance phenomenon in Suncus murinus.

METHODS: The gastrointestinal tract of adult Suncus murinus, except for the stomach and pylorus, was divided into five sections (S1, corresponding to the duodenum, S2, S3 and S4, corresponding to the jejunum and ileum, and S5, corresponding to the colon and rectum in other mammals), to investigate the PP family and their receptor-producing cells by means of immunohistochemistry.

RESULTS: NPY, PYY, Y1 and Y4-immunoreactive cells were distributed widely throughout the gastrointestinal tract, moreover, the PP family and their receptor-immunoreactive cells were predominantly distributed at the end of the gastrointestinal tract, the rectum.

CONCLUSION: In this study, we investigated the distribution of the PP family and their receptor-producing cells in the gastrointestinal tract of Suncus murinus in detail for the first time. It was presumed that the wide distribution of Y4 in the gastrointestinal tract may be related to (associated with) the phenomenon of natural obesity-resistance, visceral fat accumulation-resistance in aging Suncus murinus.