As postprandial hyperglycemia was observed in intestinal epithelial cell-specific Sirt1 KO mice, SIRTs could be the molecule connecting intestinal NAMPT-mediated NAD+ biosynthesis and canonical Wnt signaling to stimulate GLP-1 secretion [31,94] (Figure 2 and Figure 3). The gene discussed is GCG; the disease is Hyperglycemia.