Somatostatin-immunoreactive cells in the gastro-entero-pancreatic endocrine system of Xenopus laevis.

Somatostatin-like immunoreactivity has been demonstrated in cells of the gastro-entero-pancreatic endocrine system of Xenopus laevis (Amphibia) using peroxidase-anti-peroxidase immunohistochemistry. The identified cells of the gastro-intestinal tract correspond to the "Open-Paraneurons" of FUJITA (1974). Somatostatin-immunoreactive cells were found in the stomach (fundic and pyloric region), the duodenum and in the anterior ileum, but not in the colon. The dimensions of these 'Somatostatin-Open-Paraneurons' were measured: mean maximum height = 41.31 micron (S.D. = 10.87 micron), mean maximum breadth = 8.73 micron (S.D. = 2.31 micron). Frequency distributions of the maximum height and of the maximum breadth were processed by use of a computer. Somatostatin-immunoreactive cells in the pancreatic islets occupied about 15 to 25% of the total islets volume. These cells are "Closed-Paraneurons" (according to FUJITA 1974) with a mean diameter of 11.68 micron (S.D. = 2.61 micron).