[Insulin-mimetic property of vanadium compounds]

Vanadium is a transition metal which creates a number of inorganic and organic derivatives with various organic substances. Some of these compounds have pharmaceutical significance, e.g. vanadyl cation, vanadate and bis(maltolato) oxovanadium(IV). Vanadium compounds are competence inhibitors of protein tyrosine phosphatases (PTP). They have anti-tumor properties, capable of inhibiting cell proliferation at the concentrations of several micromoles. They also display insulin-mimetic and hypoglycemic properties. As they can increase the activity of the insulin-like growth factor I receptor, they stimulate glycogen synthesis, increase the number of GLUT-4 transporters in the cell membrane and impair gluconeogenesis. In addition to their effects on sugar metabolism, vanadium compounds increase the synthesis of fatty acids, reducing the concentration of glucose in the blood. Thanks to their mitotic properties, low concentrations of vanadium compounds are also able to induce β cell regeneration. Clinical tests have shown that vanadium compounds may be used as antidiabetic drugs with low toxicity. However, the range of therapeutic concentrations is very narrow; at concentrations as low a several micromoles vanadium compounds inhibit cell proliferation and cause apoptosis, necrosis and inflammation.