Pancreatic gastrin in foetal and neonatal rats

Abstract

IT has been suggested^1,2 that pancreatic gastrin is stored in islet A₁ (or D) cells. There are, however, conspicuous histological and histochemical differences between antral gastrin cells and A₁ cells, indicating the storage of different peptide molecules in these two types of cell^3,4. Furthermore, pancreatic tumours producing gastrin are composed of cells that have no features in common with A₁ cells but often resemble antral gastrin cells^5,6. We have now tested a large number of gastrin antisera, most of which were specific for the C-terminal, bioactive, sequence of gastrin-17, on both unfixed and formaldehyde-fixed tissue, and found that all antisera reacted with antral gastrin cells but not with A₁ cells. Also, radioimmunoassayable pancreatic gastrin occurs at levels far below those expected if the A₁ cells stored gastrin⁷. We conclude that if gastrin-like peptides occur in the pancreatic A₁ cells they must be devoid of the bioactive, C-terminal sequence. While studying the ontogeny of the rat gastrin cell we have, however, found, at a certain stage of development, true gastrin cells in the pancreas.