Distribution of Chromogranin Containing Cells in the Porcine Gastroenteropancreatic Endocrine System

Abstract

Regional distribution and ontogenetic time course of appearance of chromogranin (CG)-containing cells in the porcine gastroenteropancreatic (GEP) endocrine system were studied immunohistochemically. CG-immunoreactive cells were identified numerously in the gut and pancreas of adult pigs. In the overall gastrointestinal tract, they were most numerous in the fundic and pyloric gland regions of the stomach. In each portion of the gastrointestinal tract, the frequency of the CG-immunoreactive cells was higher than that of the total amount of any endocrine cells determined in our previous study. It was confirmed that all peptide/amine immunoreactive cell types except for pancreatic polypeptide-immunoreactive cells in the pancreas, and all argyrophil cell types detected by silver impregnation techniqucs, were immunoreactive with anti-CG serum. Ontogenetically, CG-immunoreactive cells had already appeared numerously in the primordial pancreas and moderately in the duodenum of 0.8 cm (18 days of gestation) porcine fetuses. In the pyloric antrum, the fundic portion and the remaining portion of the intestine, these cells appeared first in 1.5 cm (24-day-old), 3.0 cm (33-day-old) and 3.4 cm (35-day-old) fetuses, respectively. It was suggested that CG appeared much earlier than the proper peptide/amine hormones in the GEP endocrine cells at the initial stage of development. The possible significances of the early occurrence were also discussed.