Comparative Study on the Distribution of Glucagon-like Peptide-1 (GLP-1)-immunoreactive Cells in the Intestine of Chicken and Ostrich

Abstract

The distribution of glucagon-like peptide-1 (GLP-1)-immunoreactive cells was investigated in the intestine of the chicken and ostrich. GLP-1-immunoreactive endocrine cells were distributed only in the jejunum and ileum of both avian species. In chicken, these cells had a pyramidal or spindle-like shape with a cytoplasmic process and were observed at the lower part of villi and in intestinal crypts. In ostriches, endocrine cells immunoreactive with GLP-1 antiserum showed a flask- or spindle-like shape with a longer cytoplasmic process and were found in the middle and lower parts of intestinal villi. The cytoplasmic process reached to the intestinal lumen in both avian species. The frequencies of occurrence of GLP-1-immunoreactive cells in the jejunum and ileum were 19.71±8.78 and 35.82±13.87, respectively (cell numbers per mucosal area : cells/mm², mean±SD), in the chicken, and 7.72±5.50 and 6.72±3.24 in the ostrich. The difference in the frequency of occurrence of cells showing GLP-1 immunoreactivity was significant between jejunum and ileum in the chicken, but not in the ostrich. These findings suggest that GLP-1 might be one of the major hormones in the avian intestine. There is, however, a species difference in the distributional pattern of cells containing GLP-1.