The regulation of K- and L-cell activity by GLUT2 and the calcium-sensing receptor CasR in rat small intestine

Key points In intestine, nutrients including glucose and amino acids and non-nutrients including bile acids increase secretion of anti-diabetic gut peptides such as gluco-insulinotropic peptide (GIP), glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY). Facilitative glucose transporter pathways in addition to active electrogenic transporter pathways contribute to GIP, GLP-1 and PYY secretion; in particular, the facilitative glucose transporter 2 (GLUT2) is involved. Sucralose, in the presence of glucose, can strongly and acutely upregulate GIP, GLP-1 and PYY secretion in a time scale of minutes. Amino acid-stimulated GIP, GLP-1 and PYY secretion is acutely regulated by the calcium-sensing receptor (CasR). The results establish new functions for GLUT2 and CasR as regulators of gut peptide secretion that sense nutrients and provide signalling pathways for the release of GIP, GLP-1 and PYY.