Increased Expression of Heparin Binding Epidermal-Growth Factor-like Growth Factor mRNA in the Kidney of Streptozotocin-Induced Diabetic Rats

Heparin binding epidermal growth factor (HB-EGF), a new member of the EGF family, is a potent mitogen for smooth muscle cells, fibroblasts, and mesangial cells. To study whether the HB-EGF is involved in the development of diabetic nephropathy, we measured the expression of the HB-EGF gene in the kidney tissues of streptozotocin-induced diabetic rats by Northern blot analysis. The mean kidney weight of diabetic rats without strict blood sugar control was significantly increased as compared to that of the control group. Renal HB-EGF mRNA expression was also increased in diabetic rats without strict blood sugar control at 7 days after induction of diabetes and remained elevated for the entire 3-month study period. Strict insulin treatment abolished the elevation of HB-EGF mRNA expression and kidney growth. As HB-EGF is a mitogen for mesangial cells, our results suggest that HB-EGF may be involved in the development of diabetic nephropathy.