On the origin of islet parencymal cells in a cyclostome, Myxine glutinosa. A fluorescence microscopical and ultrastructural study with particular reference to endocrine cells in the bile duct mucosa

Gut hormones in cyclostomes

The current state of knowledge about regulatory peptides in endocrine cells and nerves of the alimentary canal of lampreys and hagfishes is reviewed. Cyclostomes have a wide range of peptides similar immunochemically to those of higher vertebrates. They include, in the endocrine cells of the intestine, peptides resembling glucagon, gastrin/cholecystokinin, peptide YY (pancreatic polypeptide/neuropeptide Y), substance P, vasoactive intestinal peptide, somatostatin and, in the larval stages at least, insulin. The enteric nerves of some lamprey species contain peptides resembling bombesin (gastrin-releasing peptide) and calcitonin gene-related peptide, as well as serotonin. The occurrence of other peptides is less well documented.Little is known of the molecular structure or the biological roles of the enteric peptides in cyclostomes. Extraction, purification, sequencing and physiological experiments are greatly needed.

Catecholamine-containing pancreatic islet cells of the domestic fowl. Light, fluorescence and electron microscopy, and immunohistochemistry

In an attempt to identify pancreatic islet cells emitting formaldehyde-induced fluorescence (FIF), the pancreatic islets of the domestic fowl were studied by combined fluorescence, ultrastructural, silver-impregnation and immunohistochemical methods in the same section or in consecutive semi-thin and ultra-thin sections. The results indicate that islet cells emitting intense FIF exhibit a strongly argyrophil reaction with the Grimelius' silver method and also immunohistochemical reaction with anti-glucagon serum, but not with anti-5-HT serum. Therefore, the fowl islet A cell, a peptide hormone-producing cell, stores simultaneously catecholamine as biogenic amine. The islet B and D cells did not display any FIF, any argyrophil reaction with the Grimelius' silver method, or any immunoreactivity with anti-glucagon or anti-5-HT sera. The fluorescent but non-argyrophil cells dispersed in the exocrine acinus may well be PP cells.

Localisation of somatostatin- and gastrin-like immunoreactivity in the gastrointestinal tract of Ciona intestinalis L

Somatostatin- and gastrin-like immunoreactivity has been found by immunofluorescence in cells of the stomach and intestinal epithelia of Ciona intestinalis L. The cells containing the peptide immunoreactive to mammalian anti-gastrin can be restained with Grimelius' technique for argyrophilia.

Localization of somatostatin-like immunoreactivity in the pancreatic islets of the hagfish, Myxine glutinosa and the lamprey Lampetra fluviatilis

Somatostatin-like immunofluorescence has been found by immunostaining in cells of the bile duct mucosa and pancreatic islet parenchyma of the hagfish, Myxine glutinosa, and the islet lobules of the lamprey, Lampetra fluviatilis.