bpV(phen), or potassium bisperoxo (1,10-phenanthroline) oxovanadate, is a peroxovanadium (pV) small molecule with insulin-mimetic properties. bpV(phen) and other pV compounds were demonstrated to activate insulin receptor kinase in hepatocytes and to inhibit the dephosphorylation of autophosphorylated insulin receptors, correlated to significant decreases of circulating insulin and plasma glucose levels. Inhibition of an endosomally-located protein phosphotyrosine phosphatase by bpV(phen) produces this blockade of insulin receptor dephosphorylation. bpV(phen) is also described to activate a signal pathway which abrogates dexamethasone/glucagon-induced increase of IGFBP-1 (insulin-like growth factor binding protein-1) mRNA, and this effect is suggested to be mediated through MAP kinase activity stimulated by bpV(phen) inhibition of tyrosine phosphatases involved in MAP kinase regulation.
