Co-Exposure to Bisphenol A and a High-Fat Diet Induces Insulin Resistance via Suppression of Insulin Signaling Molecule Expression and GLUT4 Translocation

While the adverse health effects of bisphenol A (BPA) or high-fat diet (HFD) exposure alone have been relatively well documented, the mechanisms underlying their combined impact on insulin resistance and type 2 diabetes remain poorly understood. In this study, we observed the effects of 90 days of treatment with BPA and an HFD on insulin resistance in mouse gastrocnemius muscle, as well as the expression of signaling molecules and proteins potentially associated with glucose transporter type 4 (GLUT4) translocation. Additionally, C2C12 myotubes were co-treated with BPA and palmitic acid (PA) to observe the effects on insulin signaling molecules, GLUT4 translocation, and insulin resistance. Specifically, in vitro cellular experiments further demonstrated that BPA and PA inhibited GLUT4 translocation from the nucleus to the cell membrane. Taken together, co-exposure to BPA and an HFD (or PA) treatment significantly altered the expression of insulin signaling molecules in both gastrocnemius muscle and C2C12 cells, suggesting a potential link to their impacts on insulin resistance and GLUT4 translocation.