Based on the results of our present study, we speculate that the following sequential events may explain the rapidly progressive renal dysfunction in diabetic TGFβ1 TG mice: a reduction in the islet β-cell mass by STZ induces a vicious cycle, where hyperglycemia increases the circulating levels of active TGFβ1, which further worsens hyperglycemia by inducing insulin resistance (Figure 9). This evidence concerns the gene TGFB1 and Insulin resistance.