A stereologic evaluation of glucagon-like peptide-1 (GLP-1) mucosal cells in the small intestine of the developing pig

Abstract.

Studies that investigate possible developmental changes in gastrointestinal hormones in the pig are sparse and contradictory. Therefore, a quantitative morphological study using stereologic methods on paraffin sections of the different small intestinal regions (cranial and caudal duodenum, jejunum and ileum) of the developing pig (second half of the gestation, neonatal and weaning period) has been conducted. The sections were processed for GLP-1-immunohistochemistry. During the investigated time span, the volume of GLP-1-IR cells increased approximately 40-fold in both the jejunum and ileum, notwithstanding a decrease of their volume density. The ileal small intestinal segment contained the highest volume density of GLP-1-IR cells. In contrast, GLP-1-IR cells were only occasionally encountered in the duodenum. The development-related changes of the investigated parameters coincide with dietary changes and the regional differences are in accordance with functional reports that point to GLP-1 as a gastrointestinal hormone that ediates the 'ileal brake' and stimulates glucose-dependent pancreatic insulin secretion.