EXPRESSION OF GLUCAGON-LIKE PEPTIDE-1 RECEPTOR IN A MURINE-C CELL-LINE - REGULATION OF CALCITONIN-GENE BY GLUCAGON-LIKE PEPTIDE-1

We have characterized, by RT-PCR amplification using specific primers, the presence of glutagon-like peptide-1 (GLP-1) receptor mRNA in CA-7 7 cells, a C fell line derived from a rat medullary thyroid carcinoma. Down-regulation of the GLP-1 receptor mRNA was observed after exposur e of CA-77 C cells Kith GLP-1 (7-37), Increased secretion of both calc itonin gene-related peptide (CGRP) and calcitonin (CT) occurred after treatment with GLP-1 (7-37) associated with elevated steady-state leve ls of CGRP and CT mRNA. GLP-1 (7-37) increased cAMP formation in CA-77 cells in a dose-dependent manner; exendin (9-39), a GLP-1 receptor an tagonist, inhibited cAMP production, The GLP-1 peptide which is produc ed by intestinal cells could be involved in the control of CT secretio n through an entero-thyroidal axis implying GLP-1 receptor and increas ed CT gene expression.