Glucagon- and PP-related peptides of intestinal L cells and pancreatic/gastric A or PP cells. Possible interrelationships of peptides and cells during evolution, fetal development and tumor growth.
The immunohistochemical detection of six distinct sequences of proglucagon and its derivatives (GRPP, glicentin, glucagon-37, glucagon-29, GLP1, GLP2 and MPGF) in both intestinal L cells and pancreatic or gastric A cells of some mammals (dog, man, guinea pig) confirms that the two cell types produce the same proglucagon molecule, although the final step of its post-translational processing differs in the two cells. Immunohistochemical and ultrastructural patterns of glucagon/glicentin cells in the pancreas of lower vertebrates and early human fetuses, as well as tumor cell studies, suggest an evolution of gastropancreatic A cells from L cells. On the contrary, the PP-related peptide PYY of intestinal L cells, and PP with its C-terminal icosapeptide extension of pancreatic PP cells, likely originate from different prohormones. Although intermediate patterns of peptide expression can be observed, including some F-type PP cells of the dog pancreas (uncinate process) and pyloric mucosa showing PYY immunoreactivity or rare PYY and/or HPP immunoreactive cells of the human rectum lacking glicentin reactivity, no obvious relationship can be established between L cells and pancreatic (F-type) PP cells. However, some evolutionary, embryogenetic and oncogenetic link may exist between L cells and human D1-type PP cells, a minor population of PP cells scattered in the pancreatic tissue of dorsal pouch origin and a major fraction of tumor PP cells.
D000818:Animals; D005075:Biological Evolution; D004285:Dogs; D005753:Gastric Mucosa / Q000378:metabolism*; D005934:Glucagon / Q000378:metabolism*; D004763:Glucagon-Like Peptides; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D007422:Intestines / Q000166:cytology / Q000196:embryology; D010179:Pancreas / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D010191:Pancreatic Polypeptide / Q000378:metabolism*; D019894:Peptide YY; D010455:Peptides / Q000378:metabolism; D052336:Proglucagon; D011498:Protein Precursors / Q000378:metabolism; D013270:Stomach / Q000166:cytology
D010455:Peptides; D011498:Protein Precursors; D019894:Peptide YY; D052336:Proglucagon; D010191:Pancreatic Polypeptide; D004763:Glucagon-Like Peptides; C015236:glucagon-like-immunoreactivity; D005934:Glucagon