Vanadium and diabetes.

Vanadium is an ultratrace element, widely distributed in nature, yet with no presently known specific physiological function in mammals. The apparent role of vanadium in regulation of intracellular signaling, as a cofactor of enzymes essential in energy metabolism, and as a possible therapeutic agent in diabetes is of increasing interest as more and more research reports present evidence of vanadium's potentially unique biological function. In this mini-review, the author summarizes current knowledge of the bioinorganic chemistry of vanadium, the basic features of diabetes mellitus and its metabolic sequelae, and the in vitro and in vivo effects of both inorganic and organically-chelated vanadium compounds. Results of clinical trials to date, as well as kinetic studies of tissue uptake are covered. Examples of ways to enhance the positive effects of vanadium as an oral therapeutic adjunct in diabetic control, while minimizing potential toxicity, are compared with regard to desirable features and possible drawbacks.