The expression of IRS-1 continued to decrease and was further lower in the DKD group than that in the DM group (P < 0.05), while the expression of pSer IRS-1 continued to increase and was higher in the DKD group than that in the DM group (P < 0.05) (Table 4 and Figure 4). This evidence concerns the gene IRS1 and diabetic kidney disease.