Oral vanadyl sulfate in treatment of diabetes mellitus in rats.

Recent reports have suggested that vanadium in the form of vanadyl (+IV) possesses insulin-like activity. Therefore, in the present study we examined the effects of administering oral vanadyl to diabetic animals. Wistar rats made diabetic with streptozotocin and age-matched controls were maintained for 10 wk in the absence and presence of vanadyl sulfate trihydrate in the drinking water. In the presence of vanadyl, decreases in rate of growth and circulating levels of insulin were the only significant alterations recorded in control animals. In contrast, diabetic animals treated with vanadyl, despite having lower body weights and insulin levels, had normal plasma concentrations of glucose, lipid, creatinine, and thyroid hormone. In addition, abnormalities in isolated working heart function and glycerol output from adipose tissue of diabetic animals were also corrected after vanadyl treatment. These results suggest that vanadium when used in the vanadyl form is effective in diminishing the diabetic state in the rat by substituting for and replacing insulin or possibly by enhancing the effects of endogenous insulin.