SMPD3 and type 2 diabetes mellitus: These results suggest that GQD can reduce the protein expression of Sptlc2 and Smpd3 in the ileum of diabetic rats by inhibiting the expression of FXR in the ileum and then reduce the source of intestinal ceramide in serum, enhance the aerobic oxidation of glucose in liver tissue, enhance glucose metabolism, and inhibit gluconeogenesis, so as to improve the symptoms of T2DM.