Expression of glucagon-like peptide-1 in the taste buds of rat circumvallate papillae

Summary on-like peptide-1 (GLP-1), a 30-amino-acid peptide hormone, is a typical peptide of the brain–gut axis and can affect the metabolism of various tissues and organs. GLP-1 is secreted by intestinal L cells in response to nutrient ingestion. Some studies have shown that taste signaling elements were co-expressed in enteroendocrine cells of the small intestine, and in particular by L-cells. The present study was performed to explore the protein and mRNA expression of GLP-1 in the taste buds of rat circumvallate papillae and to try to determine the significance of its secretion. GLP-1 immunoreactivity was observed in spindle-shaped taste bud cells, with positive cells displaying a characteristic distribution of reaction product that was confined to the cytosol. Reverse transcription polymerase chain reaction (RT-PCR) assay showed that GLP-1 mRNA was expressed in circumvallate papillae. The expression of GLP-1 suggests that it may play an important role in the taste stimulation of nutrients and gut hormone secretion.