VANADIUM SALTS AS INSULIN SUBSTITUTES - MECHANISMS OF ACTION, A SCIENTIFIC AND THERAPEUTIC TOOL IN DIABETES-MELLITUS RESEARCH

Vanadium and its compounds exhibit a wide variety of insulin-like effe cts. In this review, these effects are discussed with respect to the t reatment of type I and type II diabetes in animal models, in vitro act ions, antineoplastic role, treatment of IDDM and NIDDM patients, toxic ity, and the possible mechanism(s) involved. Newly established CytPTK plays a major role in the bioresponses of vanadium. It has a molecular weight of approximately 53 kDa and is active in the presence of Co2rather than Mn2+. Among the protein-tyrosine kinase blockers, staurosp orine is found to be a potent inhibitor of CytPTK but a poor inhibitor of InsRTK. Vanadium inhibits PTPase activity, and this in turn enhanc es the activity of protein tyrosine kinases. Our data show that inhibi tion of PTPase and protein tyrosine kinase activation has a major role in the therapeutic efficacy of vanadium in treating diabetes mellitus .