Active TGF-β serum levels before and after a test meal. T2DM patients treated with metformin and sulfonylurea (S+M), insulin glargine (G+M) or a DPP-4 inhibitor (D+M) as well as non-diabetic controls (C) received a standardized test meal. Over the course of 5 h, active TGF-β serum levels were measured at 30 min intervals. Each group consisted of 20 individuals on average. (a) Basal active TGF-β serum levels strongly depend on the pharmaceutical strategy. * p < 0.05, ** p < 0.01 and *** p < 0.001. (b) After the test meal, active TGF-β serum levels dropped after having reached their peak about 60 min after the test meal and then normalized to baseline levels. “ p < 0.05 as compared to C.