[GLP-1 receptor expression in rat major salivary glands and the effects of bilateral maxillary molar extraction on its expression].

Glucagon-like peptide 1 (GLP-1) is the gastrointestinal hormone released from L-cells of the small intestine and promotes insulin secretion by acting on the pancreas islet. GLP-1 receptor (GLP-1R) expression has been detected in many organs that are involved in carbohydrate metabolism, however its expression in the salivary glands, which participate in the first carbohydrate metabolism, has not been clarified yet. Furthermore, it is known that occlusion affects both the morphology and function of the salivary glands. Thus in this study, we focused on the expression of GLP-1R in the major salivary glands, and analyzed the changes of GLP-1R expression under the occlusal changes. Twenty-four male Wistar rats were used in this study. In the experimental group, all maxillary molars were extracted at 7 weeks old. The rats without molar extraction were used as the control group. The rats were sacrificed at 8 and 11 weeks old, then the parotid gland (PG), submandibular gland (SMG), and sublingual gland (SLG) were analyzed immunohistochemically for the presence of GLP-1R. Immunohistochemical staining showed GLP-1R to be localized in the ductal cells of PG, SMG, and SLG. In SLG, there were no differences in the intensity of GLP-1R staining in both the control and experimental groups at 8 and 11 weeks old. In PG and SMG, the intensity of GLP-1R staining in the experimental group was significantly weaker than in the control group at 11 weeks old, otherwise there were no differences at 8 weeks old. In conclusion, GLP-1R is expressed in rat PG, SMG, and SLG, and its expression can be influenced by molar extraction.