Effects of Vanadyl Sulphate on Glucose Homeostasis in Severe Diabetes Induced by Streptozotocin in Rats

Background: There is not any in vivo studies that shows inducing of euglycemia by vanadyl is independent from plasma insulin.  Therefore in the present study we planned to investigate the antidiabetic effects of vanadyl in diabetic rats. Materials and Methods: Rats became severely diabetic by an IV injection of 50-55mg/kg streptozotocin (STZ), 15 days after the injection, the blood glucose of animals was more than 500mg/dl, with plasma insulin 14±3 μu/ml that was 25% of normal rats, the daily water consumption also increased. Subsequently, the rats were divided into two groups, group I received 0.5-1 mg/ml Vanadyl sulphate in a base solution orally, and group II received base solution containing 50meq/l NaCl. Results: Vanadyl therapy for 90 days did not change blood glucose in group I from (420±10 mg/dl) to normal levels, therefore euglycaemia was achieved for a period of two months by intraperitoneal (IP) injection of NPH insulin.  The required daily doses of insulin in vanadyl-treated rats of group I (8±1 U/kg/day) were only 8 percent of those in group II animals (103±7 U/kg/day).  Conclusion: It seems that vanadyl per se cannot induce normoglycaemia in diabetic rats with very low plasma  insulin levels, but can augment the sensitivity of peripheral tissues to insulin.   Keywords: Diabetes, Insulin sensitivity, Vanadyl, Glucose, Rat