Detection of vanadyl-nitrogen interaction in organs of the vanadyl-treated rat: electron spin echo envelope modulation study.

ESEEM spectroscopy was applied for the first time to organs of an animal, viz. the kidney and liver of the rat treated with vanadyl sulfate. The aim of this study is to investigate the in vivo coordination structure of vanadyl ions administrated, and to gain information concerning the insulin-mimic activity of vanadium. ESEEM measurements for kidney and liver performed at 77 K have established nitrogen coordination to a certain percentage of vanadyl ion in the organs. The rotios of nitrogen-coordinating vanadyl ion were estimated as 70-80% in the liver, and 50-55% in the kidney. Isotropic portions of the 14N HFC were estimated as magnitude of Aiso approximately 5.0 MHz for liver, and approximately 5.2 MHz for kidney, indicating that the coordinating nitrogen is an amino nitrogen. Coordination of the Lys epsilon-amine or the N-terminal alpha-amine of a protein or (a peptide) to vanadyl ion in vivo is suggested.