Could Increased Glp1r Expression via Sitagliptin in the GLP-1/GLP-1 Receptor Axis in the Diet-Induced Obesity Rat Model be Important in Liver Metabolism?

Objective: The aim of this study was to evaluate the contribution of sitagliptin, which is used in the treatment of type 2 diabetes mellitus due to its insulinotropic effects, to the levels of glucagon-like peptide-1 (GLP-1) expressed in many systemic tissues in obesity, in liver, skeletal muscle, and fat tissue. Materials and Methods: Adult Wistar albino rats (n=32) were randomly divided into four groups for 16 weeks of intervention. These groups were control (C) (n=8), obese (Ob) (n=8), sitagliptin (C+Stg) (n=8), and obese (Ob+Stg) given sitagliptin (n=8). Glp1r expression in rat liver, muscle, and adipose tissue was confirmed by quantitative real-time PCR. Results: No significant change was detected in Glp1r expression levels in muscle and fat tissue in 4 groups. A 10.64-fold increase in Glp1r gene expression was observed in Ob compared to C (p=0.008). Additionally, a 4.03-fold increase in expression level was found in Ob+Stg compared to Ob (p=0.02) and a 12.52-fold increase in expression level was found in Ob+Stg compared to C (p=0.01). Conclusion: The increased Glp1r expression intensity in obese individuals using sitagliptin compared with controls and obese individuals not using sitagliptin may play a role in the reorganization of liver metabolism that is impaired due to obesity, such as the gluconeogenesis process. [ABSTRACT FROM AUTHOR]