Low-frequency EPR detection of chromium(V) formation by chromium(VI) reduction in whole live mice.
Measurements by direct low frequency EPR spectroscopy provide the first evidence that Cr(V) is generated in one-electron reduction of Cr(VI) in live mice. The Cr(V) yield reached a maximum about 10 min following Cr(VI) intravenous injection and then decayed slowly with a life time of approximately 37 min. The time for the Cr(V) EPR signal to reach maximum intensity increased with the dose of Cr(VI). A discernible EPR signal was still observable at a dose as low as 0.1 mmol/kg. The Cr(V) was found predominantly in the liver, with a small amount in the blood. No Cr(V) signal was detectable in heart, spleen, kidney, and lung. Pretreatment of the animals with metal ion chelators, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and 1,10-phenanthroline significantly reduced the intensity of the Cr(V) signal that was observed.
Liu
K J
KJ
Department of Radiology, Dartmouth Medical School, Hanover, New Hampshire 03755.
Jiang
J
J
Swartz
H M
HM
Shi
X
X
D000818:Animals; D002840:Chromates / Q000378:metabolism; D002857:Chromium / Q000032:analysis / Q000378:metabolism*; D003432:Cross-Linking Reagents; D004492:Edetic Acid / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D010084:Oxidation-Reduction; D004369:Pentetic Acid / Q000494:pharmacology; D010618:Phenanthrolines / Q000494:pharmacology; D013997:Time Factors
D002840:Chromates; D003432:Cross-Linking Reagents; D010618:Phenanthrolines; D002857:Chromium; D004369:Pentetic Acid; D004492:Edetic Acid; C016104:sodium bichromate; C025205:1,10-phenanthroline