Immunohistochemical and Morphometrical Studies on the Distribution of Glucagon-like Peptide-1 (GLP-1)-immunoreactive Cells in the Chicken Intestine

Abstract

The distribution of glucagon-like peptide-+ (GLP-+)-containing endocrine cells was investigated in the chicken intestine by using imunohistochemical and morphometrical techniques. GLP-+-immunoreactive cells were mainly distributed in the whole jejunum and ileum, and rarely found in ascending duodenum, but not in other intestinal regions. These cells had pyramidal or spindle-like shape and a cytoplasmic process reaching to the intestinal lumen. In jejunum immunoreactive cells were mainly observed in the middle part of villi, and in ileum they were mainly found in the lower part of villi and crypts. The frequencies of occurrence of GLP-+-immunoreactive cells in the proximal, middle and distal jejunum were +0.03ῌ1..1, ,,.*0ῌ+*.+and -/.22ῌ+/.+1, respectively (cell numbers per mucosal area : cells/mm , , meanῌSD), and those in the proximal, middle and distal ileum were .+.-1ῌ+/.*/, /-.2.ῌ+1./1 and 1-.+,ῌ+2..0. There were significant di#erences between two adjacent regions in jejunum and ileum of small intestine. These data shows that GLP-+-immunoreactive cells are distributed more densely in the distal small intestine, and GLP-+ may play an important role in this intestinal region.

Immunohistochemical distribution of glucagon‐like peptide 1 in the digestive system of different aquatic vertebrates

“…Glucagon‐like peptide 1‐positive cells were distributed in the columnar mucous epithelium and tubular glands of the digestive tract, which is consistent with the distribution of GLP‐1‐positive cells observed in the digestive tracts of rat, pig, human, cat, dog, treeshrews, salmon, rainbow trout and pheasant (Eissele et al, ; Hiramatsu, Yamasaki, & Shioji, ; Nozaki et al, ; Pirone et al, ; Pyarokhil, Ishihara, Sasaki, & Kitamura, ; Varndell et al, ). Many studies have shown that 5‐hydroxytryptamine (5‐HT)‐secreting cells, gastrin‐secreting cells, somatostatin‐secreting cells, CCK‐secreting cells and gastric inhibitory peptide‐secreting cells are also distributed in mucous epithelium and tubular glands of lamina propria of the digestive tract (Arena, Richardson, & Yamada, ; Buchan, Lance, & Pola, ; Çınar, Şenol, & Rüştü Özen, ; El‐salhy & Grimelius, ; Ku, Lee, & Lee, ; Lee, Hashimoto, Kon, & Sugimura, ; Lee & Ku, ; Masini, ).…”

Glucagon-like Peptide-1 Receptor Expression in the Pancreatic D Cells of Three Avian Species; White Leghorn Chickens, Northern Bobwhites, and Common Ostriches

“…L cells are mainly distributed in the distal ileum of the chicken alimentary tract (Hiramatsu et al, 2003(Hiramatsu et al, , 2005 and secrete GLP-1 in response to ingestion of foods (Monir et al, 2014b), particularly those containing dietary protein (Monir et al, 2014a) and amino acids (Nishimura et al, 2015). GLP-1 released from the intestinal L cells binds to its specific receptor, GLP-1R.…”

“…The mRNA of proglucagon, which acts as the precursor of GLP-1, is highly expressed in the ileum of the chicken alimentary tract (Honda et al, 2017). In chickens, GLP-1 is stored in the secretory granules of L cells, which are mainly distributed in the distal ileum (Hiramatsu et al, 2003(Hiramatsu et al, , 2005Nishimura et al, 2013) and is secreted in response to dietary protein and amino acids (Monir et al, 2014a;Nishimura et al, 2015). GLP-1 secreted from L cells binds to its specific receptor, GLP-1R.…”

Influences of protein ingestion on glucagon‐like peptide (GLP)‐1‐immunoreactive endocrine cells in the chicken ileum

“…Because frequencies of occurrence of GLP‐1‐immunoreactive cells are highest in the distal ileum and low in jejunum of the chicken small intestine (Hiramatsu et al . , ), the distal ileum (at the middle level of ceca), approximately 2 cm long, was immediately dissected from each bird after examining the gross anatomy of the abdomen. Contents of tissue samples were washed with 0.75% sodium chloride solution and immersed in Bouin's fluid at room temperature for 24 h.…”

“…Our previous immunohistochemical and morphometrical studies in the chicken intestine showed that the immunoreactive cells against GLP‐1 antiserum are mainly distributed in the whole jejunum and ileum, and rarely found in the ascending duodenum, but not observed in other intestinal regions (Hiramatsu et al . , ). These findings suggest that GLP‐1 plays an important role in the regulation of activities of the chicken small intestine.…”