IMMNNOHISTOCHEMICAL LOCALIZATION OF DIFFERENT FORMS OF SOMATOSTATIN IN THE GASTROINTESTINAL-TRACT OF THE CALF

The presence of two peptides that belong to the somatostatin family ha s been investigated in the calf gut. Somatostatin-14-like and Somatost atin-28-like peptides have been localized by a light microscopic immun ohistochemical method. The method employed antibodies linked to colloi dal gold particles that were revealed by a silver-enhancement step. So matostatin-14-like peptide was only present in mucosal endocrine cells , which were detectable along the entire gut with the exceptions of th e abomasal gastric proper glands and caecum. The cells were most abund ant in cardiac and pyloric glands. Langerhans' islets also contained t his type of endocrine cell. Somatostatin-28-like-immunoreactive endocr ine cells were more abundant than the former cell type. They were pres ent in the gastric proper glands and caecum where Somatostatin-14-like -immunoreactive cells were absent. They were as numerous as the former type of cell in the endocrine pancreas. The Somatostatin-28-like pept ide was also detectable in the intramural nervous components of the ab omasum and the intestine, in both perikarya and terminals. Our results show a possible heterogeneity of an endocrine cell type, which synthe sizes and secretes somatostatin peptides. Our results also support the hypothesis that somatostatin-14 and somatostatin-28 peptides may have distinct functional roles, particularly in different species.