Srinivasan S, et al. - This research was designed to assess the physiologic and hormonal effects of rs7903146 T allele in transcription-factor-7-like-2 (TCF7L2) genotype before and after interventions that influence glucose physiology. In people without diabetes, common variation at TCF7L2 influenced the acute responses to both glipizide and metformin. Findings underscored altered incretin signaling as a potential mechanism by which TCF7L2 variation increased type 2 diabetes (T2D) risk.