Considering these observations, we propose the possibility that increasing incretin levels through pharmacotherapy might overcome incretin resistance due to genetic variation in TCF7L2. Therefore, the objective of the present study was to evaluate whether individuals with T2DM carriers and noncarriers of the polymorphic variant rs7903146 of the TCF7L2 gene present different postprandial pancreatic hormonal responses after treatment with exenatide. The gene discussed is GCG; the disease is type 2 diabetes mellitus.