On the fate of vanadate in human blood

As a summary of recent activities at our research group, a model describing the distribution of pentavalent vanadium (referred to as vanadate throughout the present work) in human blood has been constructed based on our speciation studies performed in the physiological medium of 0.150 M Na(Cl) with various blood constituents. In addition, other data (most notably with the high mass serum constituents albumin and transferrin) have also been used to give as broad a view as possible. Two antidiabetic drug candidate ligands, picolinate and maltol, have also been included in order to investigate the stability of their vanadium complexes in the presence of blood constituents, i.e. to account for ligand-exchange possibilities. The model predicts transferrin to be the major carrier of vanadium in the bloodstream. It is capable of almost completely replacing the vanadium-bound picolinate even if the latter is in large excess. Maltol, on the other hand, can retain most of the vanadium when it is supplied in about a 5 mm concentration. The model still has certain limitations but it serves as a useful base for investigating structure, stability, relationship effects and provides insight into the fate of vanadate in human blood. (c) Wiley-VCH Verlag GmbH & Co.